View source for Organization:National Ignition Facility

{{Short description|American nuclear fusion facility}}
[[File:Exterior patio of the National Ignition Facility.jpg|thumb|upright=1.2|The National Ignition Facility, located at Lawrence Livermore National Laboratory]]
[[File:Nif-shot target-arm-before big.jpg|thumb|upright=1.2|The target assembly for NIF's first integrated [[Physics:Fusion ignition|ignition]] experiment is mounted in the cryogenic target positioning system, or cryoTARPOS. The two triangle-shaped arms form a shroud around the cold target to protect it until they open five seconds before a shot.]]

The '''National Ignition Facility''' ('''NIF''') is a [[Physics:Laser|laser]]-based [[Physics:Inertial confinement fusion|inertial confinement fusion]] (ICF) research device, located at [[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]] in Livermore, California, United States. NIF's mission is to achieve [[Physics:Fusion ignition|fusion ignition]] with high [[Physics:Fusion energy gain factor|energy gain]]. It achieved the first instance of scientific [[Physics:Fusion energy gain factor#Breakeven|breakeven]] controlled fusion in an experiment on December 5, 2022, with an energy gain factor of 1.5.<ref name=":1">{{Cite journal |last=Clery |first=Daniel |date=December 13, 2022 |title=With historic explosion, a long sought fusion breakthrough |url=https://www.science.org/content/article/historic-explosion-long-sought-fusion-breakthrough |access-date=December 13, 2022 |website=Science |doi=10.1126/science.adg2803}}</ref><ref>{{citation |journal=Physics Today |publisher=American Institute of Physics |title=National Ignition Facility surpasses long-awaited fusion milestone |author=David Kramer |date=December 13, 2022 |volume=2022 |issue=2 |pages=1213a |doi=10.1063/PT.6.2.20221213a |bibcode=2022PhT..2022b1213. |s2cid=254663644 |quote=The shot at Lawrence Livermore National Laboratory on 5 December is the first-ever controlled fusion reaction to produce an energy gain. |url=https://physicstoday.scitation.org/do/10.1063/PT.6.2.20221213a/full/}}</ref> It supports nuclear weapon maintenance and design by studying the [[Physics:Equation of state|behavior of matter]] under the conditions found within nuclear explosions.<ref>{{cite web|url=https://lasers.llnl.gov/about/ |title=About NIF & Photon Science|archive-url=https://web.archive.org/web/20171202182709/https://lasers.llnl.gov/about |archive-date=December 2, 2017 |publisher=Lawrence Livermore National Laboratory}}</ref>

NIF is the largest and most powerful ICF device built to date.<ref>{{Cite journal |last1=Hogan |first1=W.J |last2=Moses |first2=E.I |last3=Warner |first3=B.E |last4=Sorem |first4=M.S |last5=Soures |first5=J.M |date=2001 |title=The National Ignition Facility |url=https://iopscience.iop.org/article/10.1088/0029-5515/41/5/309 |journal=Nuclear Fusion |volume=41 |issue=5 |pages=567–573 |doi=10.1088/0029-5515/41/5/309 |bibcode=2001NucFu..41..567H |s2cid=250785362 |issn=0029-5515}}</ref> The basic ICF concept is to squeeze a small amount of fuel to reach pressure and temperature necessary for fusion. NIF hosts the world's most energetic [[Physics:Laser|laser]]. The laser heats the outer layer of a small sphere. The energy is so intense that it causes the sphere to implode, squeezing the fuel inside. The implosion reaches a peak speed of {{convert|350|km/s|mm/ns|abbr=on}},<ref>{{cite web |url=https://www.theengineer.co.uk/tracing-the-sources-of-nuclear-fusion/ |first=Stuart |last=Nathan |title=Tracing the sources of nuclear fusion |website=The Engineer|date=October 6, 2019 }}</ref> raising the fuel density from about that of water to about 100 times that of [[Chemistry:Lead|lead]]. The delivery of energy and the [[Physics:Adiabatic process|adiabatic process]] during implosion raises the temperature of the fuel to hundreds of millions of degrees. At these temperatures, fusion processes occur in the tiny interval before the fuel explodes outward.

Construction on the NIF began in 1997. NIF was completed five years behind schedule and cost almost four times its original budget. Construction was certified complete on March 31, 2009, by the U.S. Department of Energy.<ref name="Certified complete">{{cite web |title=Department of Energy Announces Completion of World's Largest Laser |url=https://www.energy.gov/news2009/7191.htm |publisher=United States Department of Energy |date=March 31, 2009 |access-date=April 1, 2009  |archive-url=https://web.archive.org/web/20090401194726/http://www.energy.gov/news2009/7191.htm |archive-date=April 1, 2009}}</ref> The first large-scale experiments were performed in June 2009<ref name="firstshots">{{cite web |title=First NIF Shots Fired to Hohlraum Targets |url=https://lasers.llnl.gov/newsroom/project_status/2009/june.php |publisher=National Ignition Facility |date=June 2009 |access-date=September 13, 2009  |archive-url=https://web.archive.org/web/20100528000229/https://lasers.llnl.gov/newsroom/project_status/2009/june.php |archive-date=May 28, 2010}}</ref> and the first "integrated ignition experiments" (which tested the laser's power) were declared completed in October 2010.<ref name="Oct8_10">{{cite web |title=First successful integrated experiment at National Ignition Facility announced |work=General Physics |publisher=PhysOrg.com |date=October 8, 2010 |url=http://www.physorg.com/news205740709.html |access-date=October 9, 2010}}</ref>

From 2009 to 2012 experiments were conducted under the National Ignition Campaign, with the goal of reaching ignition just after the laser reached full power, some time in the second half of 2012. The campaign officially ended in September 2012, at about {{frac|10}} the conditions needed for ignition.<ref>{{cite tech report |last=Crandall |first=David |title=Final Review of the National Ignition Campaign |url=http://fire.pppl.gov/NIF_NIC_rev6_Koonin_2012.pdf |date=December 27, 2012 |publisher=Department of Energy |page=3}}</ref><ref>{{cite book |title=An Assessment of the Prospects for Inertial Fusion Energy |url=https://books.google.com/books?id=lBKfAwAAQBAJ |publisher=National Academies Press |date=July 2013 |page=2 |isbn=978-0-309-27224-7}}</ref> Thereafter NIF has been used primarily for materials science and weapons research. In 2021, after improvements in fuel target design, NIF produced 70% of the energy of the laser, beating the record set in 1997 by the [[Physics:Joint European Torus|JET]] reactor at 67% and achieving a [[Astronomy:Burning plasma|burning plasma]].<ref name=":0" /> On December 5, 2022, after further technical improvements, NIF reached "ignition", or [[Physics:Fusion energy gain factor#Scientific breakeven at NIF|scientific breakeven]], for the first time, achieving a 154% energy yield.<ref name="igntion2022-llnl" />

== Inertial confinement fusion basics ==
[[Physics:Inertial confinement fusion|Inertial confinement fusion]] (ICF) devices use intense energy to rapidly heat the outer layers of a target in order to compress it. In an H-bomb, this is provided by a nuclear fission explosive. In non-fission devices, energy sources include laser and particle beams.<ref name=FW>{{citation |last=Winterberg |first=Friedwardt |page=2 |title=The Release of Thermonuclear Energy by Inertial Confinement: Ways Towards Ignition |date=2010 |publisher=World Scientific |isbn=978-981-4295-90-1 }}</ref>

The target is a small spherical pellet containing a few milligrams of fusion fuel, typically a mix of [[Physics:Deuterium|deuterium]] (D) and [[Physics:Tritium|tritium]] (T), as this composition has the lowest ignition temperature.{{r|FW}}

Multiple laser beams heat the surface of the pellet into a [[Physics:Plasma|plasma]], which explodes away from the surface. The rest of the pellet is driven inward on all sides, into a small volume of extremely high density. The surface explosion creates [[Physics:Shock wave|shock wave]]s that travel inward. At the center of the fuel, a small volume is further heated and compressed. When the temperature and density are high enough, fusion reactions occur.<ref name="how">{{cite web|url=https://lasers.llnl.gov/programs/nif/how_nif_works/ |title=How NIF works|archive-url=https://web.archive.org/web/20100527191346/https://lasers.llnl.gov/programs/nif/how_nif_works/ |archive-date=May 27, 2010|publisher=Lawrence Livermore National Laboratory|access-date=October 2, 2007}}</ref> The energy must be delivered quickly and spread extremely evenly across the target's outer surface in order to compress the fuel symmetrically.<ref>{{cite journal|title=Azimuthal Drive Asymmetry in Inertial Confinement Fusion Implosions on the National Ignition Facility|author=Hans G. Rinderknecht |author2=D. T. Casey |author3=R. Hatarik |author4=R. M. Bionta |author5=B. J. MacGowan |author6=P. Patel |author7=O. L. Landen |author8=E. P. Hartouni |author9=O. A. Hurricane |journal=Phys. Rev. Lett.|volume=124|number=145002 |date=10 April 2020|page=145002 |doi=10.1103/PhysRevLett.124.145002|pmid=32338973 |bibcode=2020PhRvL.124n5002R |s2cid=216305472 |quote=[A]symmetry degrades hot-spot conditions at peak convergence and limits implosion performance and yield.|doi-access=free}}</ref>

The reactions release high-energy particles, some of which, primarily [[Physics:Alpha particle|alpha particle]]s, collide with unfused fuel and heat it further, potentially triggering additional fusion. At the same time, the fuel is also losing heat through [[Physics:X-ray|x-ray]] losses and hot electrons leaving the fuel area. Thus the rate of alpha heating must be greater than the loss rate, termed ''bootstrapping''.<ref name="hurricane">{{cite web |url=https://www.llnl.gov/news/climbing-mountain-fusion-ignition-interview-omar-hurricane |title=Climbing the mountain of fusion ignition: an interview with Omar Hurricane |website=LLNL}}</ref> Given the right conditions—high enough density, temperature, and duration—bootstrapping results in a [[Philosophy:Chain reaction|chain reaction]], burning outward from the center. This is known as ''ignition'', which fuses a significant portion of the fuel and releases large amounts of energy.<ref name="econ">{{cite web |url=http://www.nuc.berkeley.edu/thyd/icf/IFE.html |title=Inertial Fusion Energy: A Tutorial on the Technology and Economics |archive-url=https://web.archive.org/web/20081221233137/http://www.nuc.berkeley.edu/thyd/icf/IFE.html |archive-date=December 21, 2008 |last=Peterson |first=Per F. |date=September 23, 1998 |access-date=October 8, 2013}}</ref>

As of 1998, most ICF experiments had used laser drivers. Other drivers have been examined, such as heavy ions driven by [[Physics:Particle accelerator|particle accelerator]]s.<ref>Per F. Peterson, [http://www.nuc.berkeley.edu/thyd/icf/target.html "How IFE Targets Work"], University of California, Berkeley, 1998. Retrieved on May 8, 2008. {{webarchive |url=https://web.archive.org/web/20080506122940/http://www.nuc.berkeley.edu/thyd/icf/target.html |date=May 6, 2008 }}</ref><ref>Per F. Peterson, [http://www.nuc.berkeley.edu/thyd/icf/driver.html "Drivers for Inertial Fusion Energy"], University of California, Berkeley, 1998. Retrieved on May 8, 2008. {{webarchive |url=https://web.archive.org/web/20080506200941/http://www.nuc.berkeley.edu/thyd/icf/driver.html |date=May 6, 2008 }}</ref>

== Design ==

=== System ===
[[File:Laser hohlraum target energy coupling.svg|thumb|left|upright=1.1|[[Sankey diagram|Sankey diagram]] of the laser energy to hohlraum x-ray to target capsule energy coupling efficiency. Note the "laser energy" is after conversion to UV, which loses about 50% of the original IR power. The conversion of x-ray heat to energy in the fuel loses another 90% – of the 1.9&nbsp;MJ of laser light, only about 10 kJ ends up in the fuel itself.]]

As of 2004, NIF used the indirect drive method of operation, in which the laser heats a small metal cylinder surrounding the capsule inside it. The heat causes the cylinder, known as a [[Physics:Hohlraum|hohlraum]] (German for "hollow room", or cavity), to re-emit the energy as even higher frequency [[Physics:X-ray|X-ray]]s, which are still more evenly distributed and symmetrical. Experimental systems, including the [[Physics:OMEGA laser|OMEGA]] and Nova lasers, validated this approach.<ref>J.D. Lindl et al., ''[http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PHPAEN000011000002000339000001&idtype=cvips&gifs=yes The physics basis for ignition using indirect-drive targets on the National Ignition Facility]'', Physics of Plasmas, Vol. 11, February 2004, page 339. Retrieved on May 7, 2008.</ref> The NIF's high power supports a much larger target; the baseline pellet design is about 2&nbsp;mm in diameter. It is chilled to about 18 kelvin (−255&nbsp;°C) and lined with a layer of frozen deuterium–tritium (DT) fuel. The hollow interior contains a small amount of DT gas.<ref>{{Cite web|url=https://www.scientificamerican.com/article/high-powered-lasers-deliver-fusion-energy-breakthrough/|title=High-Powered Lasers Deliver Fusion Energy Breakthrough|first=David|last=Biello|website=Scientific American}}</ref>

In a typical experiment, the laser generates 3&nbsp;MJ of infrared laser energy of a possible 4. About 1.5&nbsp;MJ remains after conversion to UV, and another 15 percent is lost in the hohlraum. About 15 percent of the resulting x-rays, about 150&nbsp;kJ, are absorbed by the target's outer layers.<ref name="gain">Suter, L.; J. Rothenberg, D. Munro, et al., "[http://www.llnl.gov/tid/lof/documents/pdf/237134.pdf Feasibility of High Yield/High Gain NIF Capsules]{{dead link|date=December 2022 |bot=InternetArchiveBot |fix-attempted=yes }}", Lawrence Livermore National Laboratory, December 6, 1999. Retrieved on May 7, 2008.</ref> The coupling between the capsule and the x-rays is lossy, and ultimately only about 10 to 14&nbsp;kJ of energy is deposited in the fuel.<ref>{{cite journal |last1=Hurricane |first1=O. A. |last2=Callahan |first2=D. A. |last3=Casey |first3=D. T. |last4=Dewald |first4=E. L. |last5=Dittrich |first5=T. R. |last6=Döppner |first6=T. |last7=Barrios Garcia |first7=M. A. |last8=Hinkel |first8=D. E. |last9=Berzak Hopkins |first9=L. F. |last10=Kervin |first10=P. |last11=Kline |first11=J. L. |date=May 2014 |title=The high-foot implosion campaign on the National Ignition Facility |journal=Physics of Plasmas |volume=21 |issue=5 |page=056314 |bibcode=2014PhPl...21e6314H |doi=10.1063/1.4874330 |osti=1129989 |last12=Pape |first12=S. Le |author13-link=Tammy Ma |last13=Ma |first13=T. |last14=MacPhee |first14=A. G. |last15=Milovich |first15=J. L. |last16=Moody |first16=J. |last17=Pak |first17=A. E. |last18=Patel |first18=P. K. |last19=Park |first19=H.-S. |last20=Remington |first20=B. A. |last21=Robey |first21=H. F. |last22=Salmonson |first22=J. D. |last23=Springer |first23=P. T. |last24=Tommasini |first24=R. |last25=Benedetti |first25=L. R. |last26=Caggiano |first26=J. A. |last27=Celliers |first27=P. |last28=Cerjan |first28=C. |last29=Dylla-Spears |first29=R. |last30=Edgell |first30=D. |last31=Edwards |first31=M. J. |last32=Fittinghoff |first32=D. |last33=Grim |first33=G. P. |last34=Guler |first34=N. |last35=Izumi |first35=N. |last36=Frenje |first36=J. A. |last37=Gatu Johnson |first37=M.|author37-link=Maria Gatu Johnson |last38=Haan |first38=S. |last39=Hatarik |first39=R. |last40=Herrmann |first40=H. |last41=Khan |first41=S. |last42=Knauer |first42=J. |last43=Kozioziemski |first43=B. J. |last44=Kritcher |first44=A. L. |last45=Kyrala |first45=G. |last46=Maclaren |first46=S. A. |last47=Merrill |first47=F. E. |last48=Michel |first48=P. |last49=Ralph |first49=J. |last50=Ross |first50=J. S. |last51=Rygg |first51=J. R. |last52=Schneider |first52=M. B. |last53=Spears |first53=B. K. |last54=Widmann |first54=K. |last55=Yeamans |first55=C. B.}}</ref>

The fuels in the center of the target are compressed to a density of about 1000&nbsp;g/cm<sup>3.</sup><ref name="density">{{Cite web |title=Ignition Physics Program |archive-url=https://web.archive.org/web/20060115042042/http://www7.nationalacademies.org/bpa/PLSC_Sept05_Presentation_Lindl.pdf |access-date=August 1, 2022 |last=Lindl |first=John |url=http://www7.nationalacademies.org/bpa/PLSC_Sept05_Presentation_Lindl.pdf |publisher=Lawrence Livermore National Laboratory |date=September 24, 2005 |archive-date=January 15, 2006}}</ref> For comparison, [[Chemistry:Lead|lead]] has a density of about 11&nbsp;g/cm<sup>3</sup>). The pressure is the equivalent of 300 billion [[Physics:Standard atmosphere (unit)|atmospheres]].<ref name="hurricane" />

Based on simulations, it was expected{{when|date=December 2022}} that about 20&nbsp;MJ of fusion energy would be released, resulting in a net fusion energy gain, denoted ''Q'', of about 15 (fusion energy out/UV laser energy in).<ref name="gain" /> Improvements in both the laser system and hohlraum design are expected to improve the energy absorbed by the capsule to about 420&nbsp;kJ (and thus perhaps 40 to 50 in the fuel itself), which, in turn, could generate up to 100–150&nbsp;MJ of fusion energy.<ref name="density" /> The baseline design allows for a maximum of about 45&nbsp;MJ of fusion energy release, due to the design of the target chamber.<ref name="target">M. Tobin et al., ''[http://www.osti.gov/bridge/servlets/purl/10173645-oQwjVY/native/10173645.pdf Target Area Design Basis and System Performance for NIF]'', American Nuclear Society, June 1994. Retrieved on May 7, 2008.</ref> This is the equivalent of about 11&nbsp;kg of TNT exploding.<ref>{{Cite web|url=https://www.qtransform.com/en/table/megajoules-to-tons-of-TNT.htm|title=Table megajoules to tons of TNT &#124; MJ to tTNT|website=www.qtransform.com}}</ref> Simulations suggest that a best-case implosion will produce a maximum energy of 7&nbsp;MJ, well below the physical limit of the chamber.<ref>{{cite news |first= Kenneth |last=Chang |newspaper=New York Times |date=25 September 2023 |url=https://www.nytimes.com/2023/09/25/science/nuclear-laser-fusion-nif.html |title=A Laser Fusion Breakthrough Gets a Bigger Burst of Energy}}</ref>

As of 1996, these output energies were less than the 400&nbsp;MJ<ref>{{cite web|url=https://lasers.llnl.gov/content/assets/docs/news/pk_fun_facts2.pdf|publisher=LLNL|title=NIF By the Numbers|access-date=17 December 2022}}</ref> of energy in the system's capacitors that power the laser amplifiers. The net wall-plug efficiency of NIF (UV laser energy out divided by the energy required to pump the lasers from an external source) would be less than one percent, and the total wall-to-fusion efficiency is under 10% at best. To be useful for energy production, the fusion output must be at least an order of magnitude more than this input. Commercial laser fusion systems would use much more efficient [[Physics:Diode-pumped solid-state laser|diode-pumped solid state lasers]], where wall-plug efficiencies of 10 percent have been demonstrated, and efficiencies 16–18 percent were expected with advanced concepts under development in 1996.<ref>{{cite journal |last1=Paine |first1=Stephen |last2=Marshall |first2=Christopher |date=September 1996 |title=Taking Lasers Beyond the NIF |url=https://www.llnl.gov/str/Payne.html |journal=Science and Technology Review}}</ref>

=== Laser ===
As of 2010 NIF aimed to create a single 500&nbsp;[[Watt|terawatt]] (TW) peak flash of light that reaches the target from numerous directions within a few [[Picosecond|picosecond]]s. The design uses 192 beamlines in a parallel system of flashlamp-pumped, neodymium-doped [[Chemistry:Monopotassium phosphate|phosphate glass]] lasers.<ref>{{cite news |title=Press release: NNSA and LLNL announce first successful integrated experiment at NIF |url=https://www.llnl.gov/news/nnsa-and-llnl-announce-first-successful-integrated-experiment-nif |work=Lawrence Livermore National Laboratory |date=October 6, 2010 }}</ref>

To ensure that the output of the beamlines is uniform, the laser is amplified from a single source in the Injection Laser System (ILS). This starts with a low-power flash of 1053-nanometer (nm) infrared light generated in an [[Chemistry:Ytterbium|ytterbium]]-doped optical [[Physics:Fiber laser|fiber laser]] termed Master Oscillator.<ref>P.J. Wisoff et al., ''[http://adsabs.harvard.edu/abs/2004SPIE.5341..146W NIF Injection Laser System] {{Webarchive |url=https://web.archive.org/web/20150908212244/http://adsabs.harvard.edu/abs/2004SPIE.5341..146W |date=September 8, 2015 }}'', Proceedings of SPIE Vol. 5341, pages 146–155</ref> Its light is split and directed into 48 Preamplifier Modules (PAMs). Each PAM conducts a two-stage amplification process via xenon flash lamps. The first stage is a regenerative amplifier in which the pulse circulates 30 to 60 times, increasing its energy from nanojoules to tens of millijoules. The second stage sends the light four times through a circuit containing a [[Chemistry:Neodymium|neodymium]] glass amplifier similar to (but much smaller than) the ones used in the main beamlines, boosting the millijoules to about 6&nbsp;joules. According to LLNL, designing the PAMs was one of the major challenges. Subsequent improvements allowed them to surpass their initial design goals.<ref>{{cite web|url=http://www.llnl.gov/str/Powell.html |title=Keeping Laser Development on Target for the NIF] |author=Powell|archive-url=https://web.archive.org/web/20081204100201/http://www.llnl.gov/str/Powell.html |archive-date=December 4, 2008 }}'', Lawrence Livermore National Laboratory. Retrieved on October 2, 2007</ref>

The main amplification takes place in a series of glass amplifiers located at one end of the beamlines. Before firing, the amplifiers are first [[Physics:Optical pumping|optically pumped]] by a total of 7,680 flash lamps. The lamps are powered by a [[Engineering:Capacitor|capacitor]] bank that stores 400&nbsp;MJ (110&nbsp;kWh). When the wavefront passes through them, the amplifiers release some of the energy stored in them into the beam. The beams are sent through the main amplifier four times, using an [[Pockels effect|optical switch]] located in a mirrored cavity. These amplifiers boost the original 6&nbsp;J to a nominal 4&nbsp;MJ.<ref name="how" /> Given the time scale of a few nanoseconds, the peak UV power delivered to the target reaches 500&nbsp;TW.<ref>{{Cite journal|url=https://www.tandfonline.com/doi/full/10.13182/FST94-A40247|title=Laser Design Basis for the National Ignition Facility|first1=J.T.|last1=Hunt|first2=K.R.|last2=Manes|first3=J.R.|last3=Murray|first4=P.A.|last4=Renard|first5=R.|last5=Sawicki|first6=J.B.|last6=Trenholme|first7=W.|last7=Williams|date=November 16, 1994|journal=Fusion Technology|volume=26|issue=3P2|pages=767–771|doi=10.13182/FST94-A40247|bibcode=1994FuTec..26..767H }}</ref>

Near the center of each beamline, and taking up the majority of the total length, are ''[[Physics:Spatial filter|spatial filter]]s''. These consist of long tubes with small telescopes at the end that focus the beam to a tiny point in the center of the tube, where a mask cuts off any stray light outside the focal point. The filters ensure that the beam image is extremely uniform. Spatial filters were a major step forward. They were introduced in the [[Engineering:Cyclops laser|Cyclops laser]], an earlier LLNL experiment.<ref>{{Cite web|url=https://lasers.llnl.gov/10-years-of-dedication/laser-leadership|title=45 Years of Laser Leadership|website=lasers.llnl.gov}}</ref>

The end-to-end length of the path the laser beam travels, including switches, is about {{convert|1500|m|ft}}. The various optical elements in the beamlines are generally packaged into Line Replaceable Units (LRUs), standardized boxes about the size of a [[Engineering:Vending machine|vending machine]] that can be dropped out of the beamline for replacement from below.<ref>{{cite book |doi=10.1117/12.538467 |bibcode=2004SPIE.5341..127L |chapter=NIF laser line-replaceable units (LRUs) |title=Optical Engineering at the Lawrence Livermore National Laboratory II: The National Ignition Facility |volume=5341 |page=127 |year=2004 |last1=Larson |first1=Doug W. |s2cid=122364719 |chapter-url=https://digital.library.unt.edu/ark:/67531/metadc1410354/ |editor1-last=Lane |editor1-first=Monya A |editor2-last=Wuest |editor2-first=Craig R}}</ref>

After amplification is complete the light is switched back into the beamline, where it runs to the far end of the building to the target chamber. The target chamber is a {{convert|10|m|ft|adj=mid|-diameter}} multi-piece steel sphere weighing {{convert|130000|kg}}.<ref name="Newsweek">{{cite magazine |url=http://www.newsweek.com/id/222792/ |title=Could This Lump Power the Planet? |author=Lyons, Daniel |date=November 14, 2009 |magazine=Newsweek |page=3 |access-date=November 14, 2009  |archive-url=https://web.archive.org/web/20091117020847/http://www.newsweek.com/id/222792 |archive-date=November 17, 2009}}</ref> Just before reaching the target chamber, the light is reflected off mirrors in the switchyard and target area in order to hit the target from different directions. Since the path length from the Master Oscillator to the target is different for each beamline, optics are used to delay the light in order to ensure that they all reach the center within a few picoseconds of each other.<ref>Arnie Heller, ''[https://www.llnl.gov/str/JulAug05/VanArsdall.html Orchestrating the World's Most Powerful Laser] {{Webarchive |url=https://web.archive.org/web/20081121173542/https://www.llnl.gov/str/JulAug05/VanArsdall.html |date=November 21, 2008 }}'', Science & Technology Review, July/August 2005. Retrieved on May 7, 2008</ref> <!-- NIF normally directs the laser into the chamber from the top and bottom.{{cn|date=December 2022}} -->

[[File:NIF building layout.png|thumb|upright=1.25|NIF's basic layout. The laser pulse is generated in the room just right of center, and is sent into the beamlines (blue) on either side. After several passes through the beamlines the light is sent into the "switchyard" (red) where it is aimed into the target chamber (silver).]]

One of the last steps before reaching the target chamber is to convert the infrared (IR) light at 1053&nbsp;nm into the ultraviolet (UV) at 351&nbsp;nm in a device known as a [[Physics:Optical frequency multiplier|frequency converter]].<ref>P.J. Wegner et al.,''[http://adsabs.harvard.edu/abs/2004SPIE.5341..180W NIF final optics system: frequency conversion and beam conditioning] {{Webarchive |url=https://web.archive.org/web/20150908212244/http://adsabs.harvard.edu/abs/2004SPIE.5341..180W |date=September 8, 2015 }}'', Proceedings of SPIE 5341, May 2004, pages 180–189.</ref> These are made of thin sheets (about 1&nbsp;cm thick) cut from a single crystal of potassium dihydrogen phosphate. When the 1053&nbsp;nm (IR) light passes through the first of two of these sheets, frequency addition converts a large fraction of the light into 527&nbsp;nm light (green). On passing through the second sheet, frequency combination converts much of the 527&nbsp;nm light and the remaining 1053&nbsp;nm light into 351&nbsp;nm (UV) light. [[Physics:Infrared|Infrared]] (IR) light is much less effective than UV at heating the targets, because IR couples more strongly with hot electrons that absorb a considerable amount of energy and interfere with compression. The conversion process can reach peak efficiencies of about 80 percent for a laser pulse that has a flat [[Time|temporal]] shape, but the temporal shape needed for ignition varies significantly over the duration of the pulse. The actual conversion process is about 50 percent efficient, reducing delivered energy to a nominal 1.8&nbsp;MJ.<ref>Bibeau, Camille; Paul J. Wegner, Ruth Hawley-Fedder (June 1, 2006). "[http://lfw.pennnet.com/Articles/Article_Display.cfm?Section=ARTCL&ARTICLE_ID=257238&VERSION_NUM=3&p=12 UV SOURCES: World's largest laser to generate powerful ultraviolet beams]{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}". ''Laser Focus World''. Retrieved on May 7, 2008.</ref>

As of 2010, one important aspect of any ICF research project was ensuring that experiments could be carried out on a timely basis. Previous devices generally had to cool down for many hours to allow the flashlamps and laser glass to regain their shapes after firing (due to thermal expansion), limiting their use to one or fewer firings per day. One of the goals for NIF has been to reduce this time to less than four hours, in order to allow 700 firings a year.<ref name=performance>''[https://publicaffairs.llnl.gov/news/news_releases/2003/NR-03-06-01.html NIF Project Sets Record for Laser Performance] {{webarchive |url=https://web.archive.org/web/20100528023239/https://publicaffairs.llnl.gov/news/news_releases/2003/NR-03-06-01.html |date=May 28, 2010 }}'', Lawrence Livermore National Laboratory, June 5, 2003. Retrieved on May 7, 2008.</ref>

[[File:Nif hohlraum.jpg|thumb|upright|Mockup of the gold-plated hohlraum designed for the NIF]]
[[File:Fusion microcapsule.jpg|thumb|upright|NIF's fuel "target", filled with either [[Physics:Deuterium|D]]–T gas or D–T ice. The capsule is held in the hohlraum using thin plastic webbing.]]

=== Other concepts ===
NIF is also exploring new types of targets. Previous experiments generally used plastic [[Physics:Laser ablation|ablators]], typically [[Chemistry:Polystyrene|polystyrene]] (CH). NIF targets are constructed by coating a plastic form with a layer of sputtered [[Chemistry:Beryllium|beryllium]] or beryllium–copper alloy, and then oxidizing the plastic out of the center.<ref>{{cite journal |last1=Wilson |first1=Douglas C. |last2=Bradley |first2=Paul A. |last3=Hoffman |first3=Nelson M. |last4=Swenson |first4=Fritz J. |last5=Smitherman |first5=David P. |last6=Chrien |first6=Robert E. |last7=Margevicius |first7=Robert W. |last8=Thoma |first8=D. J. |last9=Foreman |first9=Larry R. |last10=Hoffer |first10=James K. |last11=Goldman |first11=S. Robert |last12=Caldwell |first12=Stephen E. |last13=Dittrich |first13=Thomas R. |last14=Haan |first14=Steven W. |last15=Marinak |first15=Michael M. |last16=Pollaine |first16=Stephen M. |last17=Sanchez |first17=Jorge J. |title=The development and advantages of beryllium capsules for the National Ignition Facility |journal=Physics of Plasmas |date=May 1998 |volume=5 |issue=5 |pages=1953–1959 |doi=10.1063/1.872865 |bibcode=1998PhPl....5.1953W |url=https://digital.library.unt.edu/ark:/67531/metadc694360/}}</ref><ref>{{Cite web |title=Meeting the Target Challenge |url=https://www.llnl.gov/str/JulAug07/Atherton.html  |archive-url=https://web.archive.org/web/20081115130949/https://www.llnl.gov/str/JulAug07/Atherton.html |archive-date=November 15, 2008 |access-date=May 7, 2008 |publisher=Science & Technology Review}}</ref> Beryllium targets offer higher implosion efficiencies from x-ray inputs.<ref>{{Cite journal |last1=Wilson |first1=D. C. |last2=Yi |first2=S. A. |last3=Simakov |first3=A. N. |last4=Kline |first4=J. L. |last5=Kyrala |first5=G. A. |last6=Dewald |first6=E. L. |last7=Tommasini |first7=R. |last8=Ralph |first8=J. E. |last9=Olson |first9=R. E. |last10=Strozzi |first10=D. J. |last11=Celliers |first11=P. M. |last12=Schneider |first12=M. B. |last13=MacPhee |first13=A. G. |last14=Zylstra |first14=A. B. |last15=Callahan |first15=D. A. |title=X-Ray Drive of Beryllium Capsule Implosions at the National Ignition Facility |journal=Journal of Physics: Conference Series |volume=717 |doi=10.1088/1742-6596/717/1/012058 |issn=1742-6588 |last16=Hurricane |first16=O. A. |last17=Milovich |first17=J. L. |last18=Hinkel |first18=D. E. |last19=Rygg |first19=J. R. |last20=Rinderknecht |first20=H. G. |last21=Sio |first21=H. |last22=Perry |first22=T. S. |last23=Batha |first23=S.|year=2016 |issue=1 |page=012058 |bibcode=2016JPhCS.717a2058W |s2cid=114667921 |doi-access=free }}</ref>

Although NIF was primarily designed as an indirect drive device, the energy in the laser as of 2008 was high enough to be used as a direct drive system, where the laser shines directly on the target without conversion to x-rays. The power delivered by NIF UV rays was estimated to be more than enough to cause ignition, allowing [[Physics:Fusion energy gain factor|fusion energy gains]] of about 40x, somewhat higher than the indirect drive system.<ref>S. V. Weber et al., ''[http://flux.aps.org/meetings/YR9596/BAPSDPP95/abs/S6P06.html Hydrodynamic Stability of NIF Direct Drive Capsules] {{Webarchive |url=https://web.archive.org/web/20221213185556/https://flux.aps.org/meetings/YR9596/BAPSDPP95/abs/S6P06.html |date=December 13, 2022 }}'', MIXED session, November 8. Retrieved on May 7, 2008.</ref>

As of 2005, scaled implosions on the OMEGA laser and computer simulations showed NIF to be capable of ignition using a polar direct drive (PDD) configuration where the target was irradiated directly by the laser only from the top and bottom, without changes to the NIF beamline layout.<ref name=pdd>Yaakobi, B.; R. L. McCrory, S. Skupsky, et al. ''[http://www.lle.rochester.edu/pub/review/v104/104_03Polar.pdf Polar Direct Drive—Ignition at 1 MJ]'', LLE Review, Vol 104, September 2005, pp. 186–8. Retrieved on May 7, 2008 {{webarchive |url=https://web.archive.org/web/20070102194728/http://www.lle.rochester.edu/pub/review/v104/104_03Polar.pdf |date=January 2, 2007 }}</ref> <!-- In this configuration the target suffers either a "pancake" or "cigar" [[Anisotropy|anisotropy]] on implosion, reducing the maximum core temperature.{{cn|date=December 2022}} -->

As of 2005, other targets, called saturn targets, were specifically designed to reduce the anisotropy and improve the implosion.<ref>True, M. A.; J. R. Albritton, and E. A. Williams, "[http://www.lle.rochester.edu/pub/review/v102/102_01Saturn.pdf The Saturn Target for Polar Direct Drive on the National Ignition Facility], LLE Review, Vol. 102, January–March 2005, pp. 61–6. Retrieved on May 7, 2008. {{webarchive |url=https://web.archive.org/web/20080829235200/http://www.lle.rochester.edu/pub/review/v102/102_01Saturn.pdf |date=August 29, 2008 }}</ref> They feature a small plastic ring around the "equator" of the target, which becomes a plasma when hit by the laser. Some of the laser light is refracted through this plasma back towards the equator of the target, evening out the heating. NIF ignition with gains of just over 35 times are thought to be possible, producing results almost as good as the fully symmetric direct drive approach.<ref name="pdd" />

== History ==

=== Impetus, 1957 ===
The history of ICF at [[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]] in Livermore, California, started with physicist [[Biography:John Nuckolls|John Nuckolls]], who started considering the problem after a 1957 meeting arranged by [[Biography:Edward Teller|Edward Teller]] there. During these meetings, the idea later known as PACER emerged. PACER envisioned the explosion of small hydrogen bombs in large caverns to generate steam that would be converted into electrical power. After identifying problems with this approach, Nuckolls wondered how small a bomb could be made that would still generate net positive power.<ref name="EarlyNuckolls" />

A typical hydrogen bomb has two parts: a plutonium-based fission bomb known as the ''primary'', and a cylindrical arrangement of fusion fuels known as the ''secondary''. The primary releases x-rays, which are trapped within the bomb casing. They heat and compress the secondary until it ignites. The secondary consists of lithium deuteride (LiD) fuel, which requires an external neutron source. This is normally in the form of a small plutonium "spark plug" in the center of the fuel. Nuckolls's idea was to explore how small the secondary could be made, and what effects this would have on the energy needed from the primary to cause ignition. The simplest change is to replace the LiD fuel with DT gas, removing the need for the spark plug. This allows secondaries of any size – as the secondary shrinks, so does the amount of energy needed for ignition. At the milligram level, the energy levels started to approach those available through several known devices.<ref name=EarlyNuckolls>{{cite web|first=John |last=Nuckolls|url=http://www.osti.gov/bridge/servlets/purl/658936-fpqpjO/webviewable/658936.pdf |title=Early Steps Toward Inertial Fusion Energy (IFE) |archive-url=https://web.archive.org/web/20221213185556/https://www.osti.gov/biblio/658936 |archive-date=December 13, 2022 |publisher=LLNL |date=June 12, 1998}}</ref>

By the early 1960s, Nuckolls and several other weapons designers had developed ICF's outlines. The DT fuel would be placed in a small capsule, designed to rapidly ablate when heated and thereby maximize compression and shock wave formation. This capsule would be placed within an engineered shell, the hohlraum, which acts like the bomb casing. The hohlraum did not have to be heated by x-rays; any source of energy could be used as long as it delivered enough energy to heat the hohlraum and produce x-rays. Ideally the energy source would be located some distance away, to mechanically isolate both ends of the reaction. A small atomic bomb could be used as the energy source, as in a hydrogen bomb, but ideally smaller energy sources would be used. Using computer simulations, the teams estimated that about 5&nbsp;MJ of energy would be needed from the primary, generating a 1&nbsp;MJ beam.<ref name="EarlyNuckolls" /> To put this in perspective, a small (0.5&nbsp;kt ) fission primary releases 2 TJ.<ref>{{cite web|url=http://www.unitjuggler.com/convert-energy-from-kT-to-MJ.html |title=Convert kilotons, to megajoules|archive-url=https://web.archive.org/web/20221213185558/https://www.unitjuggler.com/convert-energy-from-kT-to-MJ.html |archive-date=December 13, 2022 |publisher=Unit Juggler}}</ref><ref>{{cite journal|display-authors=0 |author=Nuckolls |url=http://www.nature.com/nature/journal/v239/n5368/pdf/239139a0.pdf |title=Laser Compression of Matter to Super-High Densities: Thermonuclear (CTR) Applications|archive-url=https://web.archive.org/web/20110922173009/http://www.nature.com/nature/journal/v239/n5368/pdf/239139a0.pdf |archive-date=September 22, 2011 |journal=Nature |volume= 239|year= 1972 |page= 129}}</ref><ref>{{cite web |first=John |last=Lindl |url=http://www.osti.gov/bridge/servlets/purl/10126383-6NAuBK/native/10126383.pdf 
|title=The Edward Teller Medal Lecture: The Evolution Toward Indirect Drive and Two Decades of Progress Toward ICF Ignition and Burn|archive-url=https://web.archive.org/web/20221213185556/https://www.osti.gov/biblio/10126383 |archive-date=December 13, 2022 |publisher=11th International Workshop on Laser Interaction and Related Plasma Phenomena |date=December 1994|access-date= May 7, 2008}}</ref>

=== ICF program, 1970s ===
While Nuckolls and LLNL were working on hohlraum-based concepts, [[Organization:University of California, San Diego|UCSD]] physicist [[Biography:Keith Brueckner|Keith Brueckner]] was independently working on direct drive. In the early 1970s, Brueckner formed [[Physics:KMS Fusion|KMS Fusion]] to commercialize this concept. This sparked an intense rivalry between KMS and the weapons labs. Formerly ignored, ICF became a hot topic and most of the labs started ICF work.<ref name="EarlyNuckolls" /> LLNL decided to concentrate on glass lasers, while other facilities studied gas lasers using carbon dioxide (e.g. ANTARES, [[Organization:Los Alamos National Laboratory|Los Alamos National Laboratory]]) or KrF (e.g. [[Engineering:Nike laser|Nike laser]], Naval Research Laboratory).<ref>{{cite journal|url=https://lasers.llnl.gov/multimedia/publications/pdfs/etr/1985_02_1.pdf |title=Nova Review|journal=Energy and Technology Review}}</ref>

Throughout these early stages, much of the understanding of the fusion process was the result of computer simulations, primarily [[Physics:LASNEX|LASNEX]]. LASNEX simplified the reaction to a 2-dimensional approximation, which was all that was possible with the available computing power. LASNEX estimated that laser drivers in the kJ range could reach low gain, which was just within the state of the art.<ref name="EarlyNuckolls" /> This led to the [[Engineering:Shiva laser|Shiva laser]] project which was completed in 1977. Shiva fell far short of its goals. The densities reached were thousands of times smaller than predicted. This was traced to issues with the way the laser delivered heat to the target. Most of its energy energized electrons rather than the entire fuel mass. Further experiments and simulations demonstrated that this process could be dramatically improved by using shorter wavelengths.<ref>{{Cite web|url=https://www.llnl.gov/archives/1970s/shiva-laser-system|title=Shiva Laser System|website=www.llnl.gov}}</ref>

Further upgrades to the simulation programs, accounting for these effects, predicted that a different design would reach ignition. This system took the form of the 20-beam 200&nbsp;kJ Nova laser. During the construction phase, Nuckolls found an error in his calculations, and an October 1979 review chaired by former LLNL director [[Biography:John S. Foster Jr.|John S. Foster Jr.]] confirmed that Nova would not reach ignition. It was modified into a smaller 10-beam design that converted the light to 351&nbsp;nm and increase coupling efficiency.<ref name=peer>{{cite tech report |first1=Matthew |last1=McKinzie |first2=Christopher |last2=Paine |url=http://www.nrdc.org/nuclear/nif2/findings.asp |title=When Peer Review Fails |publisher=NDRC}}</ref> Nova was able to deliver about 30&nbsp;kJ of UV laser energy, about half of what was expected, primarily due to optical damage to the final focusing optics. Even at those levels, it was clear that the predictions for fusion production were wrong; even at the limited powers available, fusion yields were far below predictions.{{cn|date=January 2023}}

=== Halite and Centurion, 1978 ===
Each experiment showed that the energy needed to reach ignition continued to be underestimated. The Department of Energy (DOE) decided that direct experimentation was the best way to settle the issue, and in 1978 they started a series of underground experiments at the Nevada Test Site that used small nuclear bombs to illuminate ICF targets. The tests were known as Halite (LLNL) and Centurion (LANL).<ref name="auto">{{Cite book|chapter-url=https://www.sciencedirect.com/science/article/pii/B978012384656300012X|title=Fusion|first1=Garry|last1=McCracken|first2=Peter|last2=Stott|chapter=Chapter 12 – Large Inertial-Confinement Systems |editor-first1=Garry|editor-last1=McCracken|editor-first2=Peter|editor-last2=Stott|date=January 1, 2013|publisher=Academic Press|pages=149–164|doi=10.1016/B978-0-12-384656-3.00012-X |isbn=978-0-12-384656-3 |via=ScienceDirect|edition=Second }}</ref>

The basic concept behind the tests had been developed in the 1960s as a way to develop [[Engineering:Anti-ballistic missile|anti-ballistic missile]] warheads. It was found that bombs that exploded outside the atmosphere gave off bursts of X-rays that could damage an enemy warhead at long range. To test the effectiveness of this system, and to develop countermeasures to protect US warheads, the Defense Atomic Support Agency developed a system that placed the targets at the end of long tunnels behind fast-shutting doors. The doors were timed to shut in the brief period between the arrival of the X-rays and the subsequent blast. This saved the reentry vehicle (RV) from blast damage and allowed them to be inspected.<ref name="auto" />

ICF tests used the same system, replacing the RVs by hohlraums. Each test simultaneously illuminated many targets, each at a different distance from the bomb to test the effect of varying of illumination. Another question was how large the fuel assembly had to be in order for the fuel to self-heat from the fusion reactions and thus reach ignition. Initial data were available by mid-1984, and the testing ceased in 1988. Ignition was achieved for the first time during these tests. The amount of energy and the size of the fuel targets needed to reach ignition was far higher than predicted.<ref name=secretadvance>{{cite news |title=Secret Advance in Nuclear Fusion Spurs a Dispute Among Scientists |first=William |last=Broad |date=March 21, 1988 |newspaper=New York Times |url=https://www.nytimes.com/1988/03/21/us/secret-advance-in-nuclear-fusion-spurs-a-dispute-among-scientists.html}}</ref> During this same period, experiments began on Nova using similar targets to understand their behavior under laser illumination, allowing direct comparison against the bomb tests.<ref>John Lindl, "A strategy for determining the driver requirements for high gain ICF implosions utilizing hydrodynamically equivalent capsules on Nova laser", Laser Annual Program Report, 1981, Lawrence Livermore Laboratory, Livermore, CA, UCRL-50055-80/81, pp.2-29-2-57 (unpublished)</ref>

This data suggested that about 10&nbsp;MJ of X-ray energy would be needed to reach ignition, far beyond what had earlier been calculated.<ref name="secretadvance" /><ref>{{cite journal|first1=John |last1=Lindl |first2=Rober |last2=McCrory |first3=Michael |last3=Campbell |url=http://www.physics.utoronto.ca/~phy189h1/Ignition%20and%20Inertial%20Confinement%20Fusion.pdf |title=Progress Toward Ignition and Burn Propagation in Inertial Confinement Fusion|archive-url=https://web.archive.org/web/20130731181633/http://www.physics.utoronto.ca/~phy189h1/Ignition%20and%20Inertial%20Confinement%20Fusion.pdf |archive-date=July 31, 2013 |journal=Physics Today|date=September 1992 |pages= 32–40}}</ref><ref>{{cite web |url=http://classic.the-scientist.com/?articles.view/articleNo/10455/ |title=Infighting Among Rival Theorists Imperils 'Hot' Fusion Lab Plan |website=The Scientist}}</ref><ref>{{cite journal|first1=Phillip |last1=Schewe |first2= Ben |last2=Stein |url=http://nuclearweaponarchive.org/News/Lindl.txt |title=Inertial Confinement Fusion (ICF) Article Announcement|journal=Physics News|date=October 25, 1995}}</ref> If those X-rays are created by beaming an IR laser to a hohlraum, as in Nova or NIF, then dramatically more laser energy would be required, on the order of 100&nbsp;MJ.<ref name="secretadvance" />

This triggered a debate in the ICF community.<ref name="secretadvance" /> One group suggested an attempt to build a laser of this power; Leonardo Mascheroni and Claude Phipps designed a new type of hydrogen fluoride laser pumped by high-energy [[Physics:Electron|electron]]s and reach the 100&nbsp;MJ threshold. Others used the same data and new versions of their computer simulations to suggest that careful shaping of the laser pulse and more beams spread more evenly could achieve ignition with a laser powered between 5 and 10&nbsp;MJ.<ref>{{cite journal |url=http://www.osti.gov/bridge/servlets/purl/6686429-47queD/6686429.pdf |title=Information Bridge: DOE Scientific and Technical Information – Sponsored by OSTI<!-- Bot generated title --> |date=September 28, 1988 |website=osti.gov |last1=Storm |first1=E.}}</ref><ref>John Lindl, Development of the Indirect-Drive Approach to Inertial Confinement Fusion and the Target Physics Basis for Ignition and Gain, Physics of Plasmas Vol. 2, No. 11, November 1995; pp. 3933–4024</ref>

These results prompted the DOE to request a custom military ICF facility named the "Laboratory Microfusion Facility" (LMF). LMF would use a driver on the order of 10&nbsp;MJ, delivering fusion yields of between 100 and 1,000&nbsp;MJ. A 1989–1990 review of this concept by the National Academy of Sciences suggested that LMF was too ambitious, and that fundamental physics needed to be further explored. They recommended further experiments before attempting to move to a 10&nbsp;MJ system. Nevertheless, the authors noted, "Indeed, if it did turn out that a 100 MJ driver were required for ignition and gain, one would have to rethink the entire approach to, and rationale for, ICF".<ref>{{cite journal | url=https://link.springer.com/content/pdf/10.1007/BF01050621.pdf | doi=10.1007/BF01050621 | title=Review of the department of energy's inertial confinement fusion program | year=1991 | last1=Koonin | first1=Steven E. | last2=Carrier | first2=George F. | last3=Christy | first3=Robert F. | last4=Conn | first4=Robert W. | last5=Davidson | first5=Ronald C. | last6=Dawson | first6=John M. | last7=Demaria | first7=Anthony J. | last8=Doty | first8=Paul M. | last9=Happer | first9=William | last10=Kulcinski | first10=Gerald L. | last11=Longmire | first11=Conrad L. | last12=Powell | first12=James R. | last13=Rosenbluth | first13=Marshall N. | last14=Ruina | first14=Jack P. | last15=Sproull | first15=Robert L. | last16=Tigner | first16=Maury | last17=Wagner | first17=Richard L. | journal=Journal of Fusion Energy | volume=10 | issue=2 | pages=157–172 | bibcode=1991JFuE...10..157K | s2cid=122974976 }}</ref>

=== Laboratory Microfusion Facility and Nova Upgrade, 1990 ===
As of 1992, the Laboratory Microfusion Facility was estimated to cost about $1&nbsp;billion.<ref name=upgrade>''Nova Upgrade – A Proposed ICF Facility to Demonstrate Ignition and Gain'', Lawrence Livermore National Laboratory ICF Program, July 1992  https://ui.adsabs.harvard.edu/abs/1992nupi.rept....../abstract</ref> LLNL initially submitted a design with a 5&nbsp;MJ 350&nbsp;nm (UV) driver that would be able to reach about 200&nbsp;MJ yield, which was enough to attain the majority of the LMF goals.That program was estimated to cost about $600&nbsp;million FY 1989 dollars. An additional $250&nbsp;million would pay to upgrade it to a full 1,000&nbsp;MJ. The total would surpass $1&nbsp;billion to meet all of the goals requested by the DOE.<ref name="upgrade" /> <!-- Other labs proposed LMF designs using other technologies.{{cn|date=December 2022}} -->

The NAS review led to a reevaluation of these plans, and in July 1990, LLNL responded with the Nova Upgrade, which would reuse most of Nova, along with the adjacent Shiva facility. The resulting system would be much lower power than the LMF concept, with a driver of about 1&nbsp;MJ.<ref>Tobin, M.T et al., ''[http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel2/578/5735/00218762.pdf?tp=&isnumber=&arnumber=218762 Target area for Nova Upgrade: containing ignition and beyond] {{Webarchive |url=https://web.archive.org/web/20090406031502/http://ieeexplore.ieee.org/Xplore/login.jsp?url=%2Fiel2%2F578%2F5735%2F00218762.pdf%3Ftp%3D&isnumber=&arnumber=218762 |date=April 6, 2009 }}'', Fusion Engineering, 1991, pg. 650–655. Retrieved on May 7, 2008.</ref> The new design included features that advanced the state of the art in the driver section, including multi-pass in the main amplifiers, and 18 beamlines (up from 10) that were split into 288 "beamlets" as they entered the target area. The plans called for the installation of two main banks of beamlines, one in the existing Nova beamline room, and the other in the older Shiva building next door, extending through its laser bay and target area into an upgraded Nova target area. The lasers would deliver about 500&nbsp;TW in a 4&nbsp;ns pulse. The upgrades were expected to produce fusion yields of between 2 and 10&nbsp;MJ. The initial estimates from 1992 estimated construction costs around $400&nbsp;million, with construction taking place from 1995 to 1999.<ref name="upgrade" />

=== NIF, 1994 ===
Throughout this period, the ending of the [[History:Cold War|Cold War]] led to dramatic changes in defense funding and priorities. The political support for nuclear weapons declined and arms agreements led to a reduction in warhead count and less design work. The US was faced with the prospect of losing a generation of nuclear weapon designers able to maintain existing stockpiles, or design new weapons.<ref>William Broad, ''[https://query.nytimes.com/gst/fullpage.html?res=9D0DE4D9133DF932A15755C0A962958260 Vast Laser Plan Would Further Fusion and Keep Bomb Experts] {{Webarchive |url=https://web.archive.org/web/20221213185557/https://www.nytimes.com/1994/06/21/science/vast-laser-plan-would-further-fusion-and-keep-bomb-experts.html |date=December 13, 2022 }}'', New York Times, June 21, 1994. Retrieved on May 7, 2008.</ref> At the same time, the Comprehensive Nuclear-Test-Ban Treaty (CNTB) was signed in 1996, which would ban all [[Physics:Critical mass|criticality]] testing and made the development of newer generations of nuclear weapons more difficult.

[[File:Preamplifier at the National Ignition Facility.jpg|left|upright=1.25|thumb|The preamplifiers of the National Ignition Facility are the first step in increasing the energy of laser beams as they make their way toward the target chamber. In 2012 NIF achieved a 500 terawatt shot—1,000 times more power than the United States uses at any instant in time.]]
Out of these changes came the Stockpile Stewardship and Management Program (SSMP), which, among other things, included funds for the development of methods to design and build nuclear weapons without having to test them explosively. In a series of meetings that started in 1995, an agreement formed between the labs to divide up SSMP efforts. An important part of this would be confirmation of computer models using low-yield ICF experiments. The Nova Upgrade was too small to use for these experiments.<ref>Letter from Charles Curtis, Undersecretary of Energy, June 15, 1995</ref>{{efn|It is not clearly stated why Nova Upgrade would be too small for SSMP, no reason is given in the available resources.}} A redesign matured into NIF in 1994. The estimated cost of the project remained almost $1&nbsp;billion, with completion in 2002.<ref>{{Cite web|url=https://www.laserfocusworld.com/test-measurement/research/article/16551113/photonic-frontiers-the-national-ignition-facility-nif-is-up-and-running-at-last|title=Photonic Frontiers: The National Ignition Facility: NIF is up and running at last|website=www.laserfocusworld.com|date=November 2009 }}</ref>

In spite of the agreement, the large project cost combined with the ending of similar projects at other labs resulted in critical comments by scientists at other labs, [[Organization:Sandia National Laboratories|Sandia National Laboratories]] in particular. In May 1997, Sandia fusion scientist Rick Spielman publicly stated that NIF had "virtually no internal peer review on the technical issues" and that "Livermore essentially picked the panel to review themselves".<ref>"Livermore's costly fusion laser won't fly, scientists say", Albuquerque Tribune, May 29, 1997, p. 1</ref> A retired Sandia manager, Bob Puerifoy, was even more blunt than Spielman: "NIF is worthless ... it can't be used to maintain the stockpile, period".<ref>L. Spohn, "NIF opponents to cite criticism of laser in court battle", Albuquerque Tribune, June 13, 1997, p. A15.</ref> [[Biography:Ray Kidder|Ray Kidder]], one of the original developers of the ICF concept at LLNL, was also highly critical. He stated in 1997 that its primary purpose was to "recruit and maintain a staff of theorists and experimentalists" and that while some of the experimental data would prove useful for weapons design, differences in the experimental setup limit their relevance. "Some of the physics is the same; but the details, 'wherein the devil lies,' are quite different. It would therefore also be wrong to assume that NIF will be able to support for the long term a staff of weapons designers and engineers with detailed design competence comparable to that of those now working at the weapons design laboratories."<ref>{{cite journal |journal=Nature |date=April 17, 1997 |volume=386 |first=Ray |last=Kidder |title=Problems with stockpile stewardship |issue=6626 |pages=645–647 |doi=10.1038/386645a0 |bibcode=1997Natur.386..645K |s2cid=4268081 |url=http://web.mit.edu/sts/SSBS/kidder.html |archive-url=https://web.archive.org/web/20040923102841/http://web.mit.edu/sts/SSBS/kidder.html |archive-date=September 23, 2004 }}</ref>

In 1997, Victor Reis, assistant secretary for Defense Programs within DOE and SSMP chief architect defended the program telling the U.S. House Armed Services Committee that NIF was "designed to produce, for the first time in a laboratory setting, conditions of temperature and density of matter close to those that occur in the detonation of nuclear weapons. The ability to study the behavior of matter and the transfer of energy and radiation under these conditions is key to understanding the basic physics of nuclear weapons and predicting their performance without underground nuclear testing."<ref>Statement of Dr. Victor Reis, Assistant Secretary for Defense Programs, Department of Energy, before the Senate Armed Services Committee, March 19, 1997 (retrieved July 13, 2012, from http://www.lanl.gov/orgs/pa/Director/reisSASC97.html {{Webarchive |url=https://web.archive.org/web/20050104210728/http://www.lanl.gov/orgs/pa/Director/reisSASC97.html |date=January 4, 2005 }} )</ref> In 1998, two JASON panels, composed of scientific and technical experts, stated that NIF is the most scientifically valuable of all programs proposed for science-based stockpile stewardship.<ref>{{cite web |url=http://www.armed-services.senate.gov/statemnt/980326fp.htm |title=Statement of Federico Peña, Secretary, US Dept of Energy, before the Committee on Armed Services, United States Senate |date=March 26, 1998 |access-date=July 13, 2012  |archive-url=https://web.archive.org/web/20110205200200/http://armed-services.senate.gov/statemnt/980326fp.htm |archive-date=February 5, 2011}}</ref>

Despite the initial criticism, Sandia, as well as Los Alamos, supported the development of many NIF technologies,<ref>{{cite report |url=http://www.osti.gov/bridge/purl.cover.jsp?purl=/274120-bKjglv/webviewable/274120.pdf |title=Information Bridge: DOE Scientific and Technical Information – Sponsored by OSTI |publisher=Osti.gov |date=August 31, 2012 |access-date=October 8, 2012 |last1=Boyes |first1=J. |last2=Boyer |first2=W. |last3=Chael |first3=J. |last4=Cook |first4=D. |last5=Cook |first5=W. |last6=Downey |first6=T. |last7=Hands |first7=J. |last8=Harjes |first8=C. |last9=Leeper |first9=R. |last10=McKay |first10=P. |last11=Micano |first11=P. |last12=Olson |first12=R. |last13=Porter |first13=J. |last14=Quintenz |first14=J. |last15=Roberts |first15=V. |last16=Savage |first16=M. |last17=Simpson |first17=W. |last18=Seth |first18=A. |last19=Smith |first19=R. |last20=Wavrik |first20=M. |last21=Wilson |first21=M.}}</ref> and both laboratories later{{when|date=December 2022}} became partners with NIF in the National Ignition Campaign.<ref>{{cite web |url=https://lasers.llnl.gov/programs/nic/participants.php |title=National Ignition Campaign: Participants, NIF & Photon Science |publisher=Lasers.llnl.gov |access-date=October 8, 2012  |archive-url=https://web.archive.org/web/20121017203631/https://lasers.llnl.gov/programs/nic/participants.php |archive-date=October 17, 2012}}</ref>

=== Construction of first unit, 1994–1998 ===
[[File:Beamlet Laser.jpg|thumb|The Beamlet laser tested the design and techniques that would be used on NIF.]]
[[File:NIF target chamber construction.jpg|thumb|The NIF target chamber was so large it had to be built in sections.]]
Work on the NIF started with a single beamline demonstrator, Beamlet. Beamlet successfully operated between 1994 and 1997. It was then sent to [[Organization:Sandia National Laboratories|Sandia National Laboratories]] as a light source in their [[Organization:Z Pulsed Power Facility|Z machine]]. A full-sized demonstrator then followed, in AMPLAB, which started operations in 1997.<ref>J. A. Horvath, ''[https://e-reports-ext.llnl.gov/pdf/234367.pdf Assembly and Maintenance of Full Scale NIF Amplifiers in the Amplifier Module Prototype Laboratory (AMPLAB)] {{Webarchive |url=https://web.archive.org/web/20150908212244/https://e-reports-ext.llnl.gov/pdf/234367.pdf |date=September 8, 2015 }}'', Third Annual International Conference on Solid State Lasers for Application (SSLA) to Inertial Confinement Fusion (ICF), July 16, 1998</ref> The official groundbreaking on the main NIF site was on May 29, 1997.<ref>{{cite web |url=https://lasers.llnl.gov/multimedia/photo_gallery/building_nif/?id=1&category=building_nif |title=Multimedia: Photo Gallery, NIF & Photon Science |publisher=Lasers.llnl.gov |date=May 29, 1997 |access-date=October 8, 2012  |archive-url=https://web.archive.org/web/20120724042234/https://lasers.llnl.gov/multimedia/photo_gallery/building_nif/?id=1&category=building_nif |archive-date=July 24, 2012}}</ref>

At the time, the DOE was estimating that the NIF would cost approximately $1.1&nbsp;billion and another $1&nbsp;billion for related research, and would be complete as early as 2002.<ref name=GAO1>''[http://www.gao.gov/archive/2000/rc00141.pdf NATIONAL IGNITION FACILITY, Management and Oversight Failures Caused Major Cost Overruns and Schedule Delays]{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}'', GAO, August 2000</ref> Later in 1997 the DOE approved an additional $100&nbsp;million in funding and pushed the operational date back to 2004. As late as 1998 LLNL's public documents stated the overall price was $1.2&nbsp;billion, with the first eight lasers coming online in 2001 and full completion in 2003.<ref>{{Cite journal|first1=Howard T. |last1=Powell |first2=Richard H. |last2=Sawicki |title= Keeping Laser Development on Target for the National Ignition Facility|date= March 1998 |url=https://str.llnl.gov/ |access-date=October 9, 2023|archive-url=https://web.archive.org/web/20100528222944/https://www.llnl.gov/str//Powell.html |archive-date=May 28, 2010 |journal=S&TR}}</ref>

The facility's physical scale alone made the construction project challenging. By the time the "conventional facility" (the shell for the laser) was complete in 2001, more than 210,000 cubic yards of soil had been excavated, more than 73,000 cubic yards of concrete had been poured, 7,600 tons of reinforcing steel rebar had been placed, and more than 5,000 tons of structural steel had been erected. To isolate the laser system from vibration, the foundation of each laser bay was made independent of the rest of the structure. Three-foot-thick, 420-foot-long and 80-foot-wide slabs required continuous concrete pours to achieve their specifications.<ref name="LLNL newsline">{{cite web |url=https://newsline.llnl.gov/employee/articles/2001/10-26-01newsline.pdf |title=NIF conventional facility complete |work=Newsline |publisher=LLNL |date=October 26, 2001 |access-date=September 6, 2012  |archive-url=https://web.archive.org/web/20120726024319/https://newsline.llnl.gov/employee/articles/2001/10-26-01newsline.pdf |archive-date=July 26, 2012}}</ref>

In November 1997, an [[Earth:El Niño|El Niño]] storm dumped two inches of rain in two hours, flooding the NIF site with 200,000 gallons of water just three days before the scheduled foundation pour. The earth was so soaked that the framing for the retaining wall sank six inches, forcing the crew to disassemble and reassemble it.<ref name="LLNL newsline" /> Construction was halted in December 1997, when 16,000-year-old [[Biology:Mammoth|mammoth]] bones were discovered. Paleontologists were called in to remove and preserve the bones, delaying construction by four days.<ref>{{cite web |url=https://lasers.llnl.gov/education/fusion_fun/niffy.php |title=Fusion Fun: NIFFY, NIF & Photon Science |publisher=Lasers.llnl.gov |access-date=October 8, 2012  |archive-url=https://web.archive.org/web/20130125052443/https://lasers.llnl.gov/education/fusion_fun/niffy.php |archive-date=January 25, 2013}}</ref>

A variety of research and development, technology and engineering challenges arose, such as creating an optics fabrication capability to supply the laser glass for NIF's 7,500 meter-sized optics. State-of-the-art optics measurement, coating and finishing techniques were developed to withstand NIF's high-energy lasers, as were methods for amplifying the laser beams to the needed energy levels.<ref>{{cite web |last=Osolin |first=Charles |url=http://www.innovation-america.org/harnessing-power-light |title=Harnessing the Power of Light |publisher=Innovation America |access-date=October 8, 2012}}</ref> Continuous-pour glass, rapid-growth crystals, innovative optical switches, and deformable mirrors were among NIF's technology innovations developed.<ref>{{cite web |url=https://lasers.llnl.gov/about/nif/seven_wonders.php |title=National Ignition Facility: The Seven Wonders of NIF, NIF & Photon Science |publisher=Lasers.llnl.gov |access-date=October 8, 2012  |archive-url=https://web.archive.org/web/20121017204200/https://lasers.llnl.gov/about/nif/seven_wonders.php |archive-date=October 17, 2012}}</ref>

Sandia, with extensive experience in pulsed power delivery, designed the capacitor banks used to feed the flashlamps, completing the first unit in October 1998. To everyone's surprise, the Pulsed Power Conditioning Modules (PCMs) suffered capacitor failures that led to explosions. This required a redesign of the module to contain the debris, but since the concrete had already been poured, this left the new modules so tightly packed that in-place maintenance was impossible. Another redesign followed, this time allowing the modules to be removed from the bays for servicing.<ref name="peer" /> Continuing problems further delayed operations, and in September 1999, an updated DOE report stated that NIF required up to $350&nbsp;million more and completion occur only in 2006.<ref name="GAO1" />

=== Re-baseline and GAO report, 1999–2000 ===
[[File:Bill Richardson, official DOE photo.png|thumb|Bill Richardson began a review process that brought NIF construction back under control.]]

Throughout this period the problems with NIF were not reported up the management chain. In 1999 then Secretary of Energy Bill Richardson reported to Congress that NIF was on time and budget, as project leaders had reported. In August that year it was revealed that neither claim was close to the truth.<ref name=nyt>James Glanz, ''[https://www.nytimes.com/library/national/science/081900sci-laser-missiles.html Laser Project Is Delayed and Over Budget] {{Webarchive |url=https://web.archive.org/web/20160603090058/http://www.nytimes.com/library/national/science/081900sci-laser-missiles.html |date=June 3, 2016 }}'', New York Times, August 19, 2000. Retrieved on May 7, 2008.</ref> As the [[Engineering:Government Accountability Office|Government Accountability Office]] (GAO) would later note, "Furthermore, the Laboratory's former laser director, who oversaw NIF and all other laser activities, assured Laboratory managers, DOE, the university, and the Congress that the NIF project was adequately funded and staffed and was continuing on cost and schedule, even while he was briefed on clear and growing evidence that NIF had serious problems".<ref name="GAO1" /> A DOE Task Force reported to Richardson in January 2000 that "organizations of the NIF project failed to implement program and project management procedures and processes commensurate with a major research and development project... [and that] ...no one gets a passing grade on NIF Management: not the DOE's office of Defense Programs, not the Lawrence Livermore National Laboratory and not the University of California".<ref>''[http://www.seab.energy.gov/publications/nif_rpt.pdf Interim Report of the National Ignition Facility Laser System Task Force]'', Secretary of Energy Advisory Board, January 10, 2000. Retrieved on May 7, 2008. {{webarchive |url=https://web.archive.org/web/20070629215119/http://www.seab.energy.gov/publications/nif_rpt.pdf |date=June 29, 2007 }}</ref>

Given the budget problems, the US Congress requested an independent GAO review. They returned a critical report in August 2000 estimating that the cost was likely to be $3.9 billion, including R&D, and that the facility was unlikely to be completed anywhere near on time.<ref name="GAO1" /><ref name=fas101>''[http://www.aip.org/fyi/2000/fyi00.101.htm GAO Report Cites New NIF Cost Estimate]{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}'', FYI, American Institute of Physics, Number 101: August 30, 2000. Retrieved on May 7, 2008.</ref> The report noted management problems for the overruns, and criticized the program for failing to budget money for target fabrication, including it in operational costs instead of development.<ref name="nyt" />

In 2000, the DOE began a comprehensive "rebaseline review" because of the technical delays and project management issues, and adjusted the schedule and budget accordingly. John Gordon, National Nuclear Security Administrator, stated "We have prepared a detailed bottom-up cost and schedule to complete the NIF project... The independent review supports our position that the NIF management team has made significant progress and resolved earlier problems".<ref>Ian Hoffman, ''[http://lanl-the-rest-of-the-story.blogspot.com/2007/06/nuclear-testing-gear-in-doubt-livermore.html Nuclear testing gear in doubt] {{Webarchive |url=https://web.archive.org/web/20110708050138/http://lanl-the-rest-of-the-story.blogspot.com/2007/06/nuclear-testing-gear-in-doubt-livermore.html |date=July 8, 2011 }}'', MediaNews Group,</ref> The report revised their budget estimate to $2.25&nbsp;billion, not including related R&D which pushed it to $3.3&nbsp;billion total, and pushed back the completion date to 2006 with the first lines coming online in 2004.<ref name=fas65>''[http://www.aip.org/fyi/2000/fyi00.065.htm New Cost and Schedule Estimates for National Ignition Facility]{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}'', FYI: The API Bulletin of Science Policy News, American Institute of Physics. Retrieved on May 7, 2008.</ref><ref>''[http://www-ferp.ucsd.edu/FPA/ARC00/fpn00-29.shtml More on New NIF Cost and Schedule]{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}'', FYI, American Institute of Physics, Number 65, June 15, 2000. Retrieved on May 7, 2008.</ref> A follow-up report the next year pushed the budget to $4.2 billion, and the completion date to 2008.[[File:NIF Laser Bay.jpg|thumb|Laser Bay 2 was commissioned in July 2007.]]
The project got a new management team<ref>''LLNL Management Changes'', Fusion Power Associates,
September 10, 1999, http://aries.ucsd.edu/FPA/ARC99/fpn99-43.shtml {{Webarchive |url=https://web.archive.org/web/20160304131237/http://aries.ucsd.edu/FPA/ARC99/fpn99-43.shtml |date=March 4, 2016 }} (retrieved July 13, 2012)</ref><ref>''Campbell Investigation Triggers Livermore Management Changes'', Fusion Power Report, Sep 1, 1999
http://www.thefreelibrary.com/Campbell+Investigation+Triggers+Livermore+Management+Changes.-a063375944 {{Webarchive |url=https://web.archive.org/web/20160305134849/http://www.thefreelibrary.com/Campbell+Investigation+Triggers+Livermore+Management+Changes.-a063375944 |date=March 5, 2016 }} (retrieved July 13, 2012)</ref> in September 1999, headed by [[Biography:George H. Miller (physicist)|George Miller]], who was named acting associate director for lasers. [[Biography:Ed Moses (physicist)|Ed Moses]], former head of the [[Physics:Atomic vapor laser isotope separation|Atomic Vapor Laser Isotope Separation]] (AVLIS) program at LLNL, became NIF project manager. Thereafter, NIF management received many positive reviews and the project met the budgets and schedules approved by Congress. In October 2010, the project was named "Project of the Year" by the Project Management Institute, which cited NIF as a "stellar example of how properly applied project management excellence can bring together global teams to deliver a project of this scale and importance efficiently."<ref>{{cite web |url=https://www.llnl.gov/news/newsreleases/2010/Oct/NR-10-10-03.html |title=National Ignition Facility wins prestigious 2010 project of the year award |author=<!--Staff writer(s); no by-line.--> |date=October 11, 2010 |website=llnl.gov |publisher=[[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]] |access-date=July 13, 2012 |archive-date=July 26, 2012 |archive-url=https://web.archive.org/web/20120726024036/https://www.llnl.gov/news/newsreleases/2010/Oct/NR-10-10-03.html  }}</ref>

=== Tests and construction completion, 2003–2009 ===
In May 2003, the NIF achieved "first light" on a bundle of four beams, producing a 10.4 kJ IR pulse in a single beamline.<ref name="performance" /> In 2005 the first eight beams produced 153 kJ of IR, eclipsing OMEGA as the planet's highest energy laser (per pulse). By January 2007 all of the LRUs in the Master Oscillator Room (MOOR) were complete and the computer room had been installed. By August 2007, 96 laser lines were completed and commissioned, and "A total infrared energy of more than 2.5 megajoules has now been fired. This is more than 40 times what the Nova laser typically operated at the time it was the world's largest laser".<ref>''[https://publicaffairs.llnl.gov/news/news_releases/2007/NR-07-11-05.html World's largest laser picks up the pace] {{webarchive |url=https://web.archive.org/web/20100527234734/https://publicaffairs.llnl.gov/news/news_releases/2007/NR-07-11-05.html |date=May 27, 2010 }}'', Lawrence Livermore National Laboratory, November 21, 2007. Retrieved on May 7, 2008.</ref>

In 2005, an independent review by the JASON Defense Advisory Group that was generally positive, concluded that "The scientific and technical challenges in such a complex activity suggest that success in the early attempts at ignition in 2010, while possible, is unlikely".<ref name=jason>''[http://www.fas.org/irp/agency/dod/jason/nif.pdf NIF Ignition] {{Webarchive |url=https://web.archive.org/web/20090424080032/http://www.fas.org/irp/agency/dod/jason/nif.pdf |date=April 24, 2009 }}'', JASON Program, June 29, 2005</ref> On January 26, 2009, the final line replaceable unit (LRU) was installed,<ref>{{cite web |url=https://newsline.llnl.gov/_rev02/articles/2009/jan/01.30.09-nif.php |title=Last of 6,206 modules installed in NIF |last=Hirschfeld |first=Bob |publisher=Lawrence Livermore National Laboratory |date=January 30, 2009 |access-date=April 3, 2009  |archive-url=https://web.archive.org/web/20110718033618/https://newsline.llnl.gov/_rev02/articles/2009/jan/01.30.09-nif.php |archive-date=July 18, 2011}}</ref> unofficially completing construction.<ref name="complete">{{cite news |title=Project Status February 2009 |publisher=[[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]] |date=February 26, 2009 |url=https://lasers.llnl.gov/newsroom/project_status/2009/february.php |access-date=March 11, 2009  |archive-url=https://web.archive.org/web/20100528000209/https://lasers.llnl.gov/newsroom/project_status/2009/february.php |archive-date=May 28, 2010}}</ref> On February 26, 2009, NIF fired all 192 laser beams into the target chamber.<ref>{{cite web |url=https://newsline.llnl.gov/_rev02/articles/2009/mar/03.06.09-nif.php |title=NIF's future ignites with 192-beam shot |author=Seaver, Lynda |author2=Hirschfeld, Bob |publisher=Lawrence Livermore National Laboratory |date=March 6, 2009 |access-date=April 3, 2009  |archive-url=https://web.archive.org/web/20100528020137/https://newsline.llnl.gov/_rev02/articles/2009/mar/03.06.09-nif.php |archive-date=May 28, 2010}}</ref> On March 10, 2009, NIF became the first laser to break the megajoule barrier, delivering 1.1&nbsp;MJ of UV light, known as 3ω (from third-harmonic generation), to the target chamber center in a shaped ignition pulse.<ref>{{cite web |url=https://newsline.llnl.gov/_rev02/articles/2009/mar/03.13.09-nif.php |title=NIF breaks megaJoule barrier |publisher=Lawrence Livermore National Laboratory |date=March 13, 2009 |access-date=April 3, 2009  |archive-url=https://web.archive.org/web/20100527202123/https://newsline.llnl.gov/_rev02/articles/2009/mar/03.13.09-nif.php |archive-date=May 27, 2010}}</ref> The main laser delivered 1.952&nbsp;MJ of IR.<ref>{{Cite web|url=https://www.llnl.gov/news/nif-breaks-megajoule-barrier|title=NIF breaks megaJoule barrier|website=LLNL.gov }}</ref>

=== Operations, 2009–2012 ===
On May 29, 2009, the NIF was dedicated in a ceremony attended by thousands.<ref name="dedication">{{cite web |date=May 29, 2009 |title=Dedication of world's largest laser marks the dawn of a new era |url=https://publicaffairs.llnl.gov/news/news_releases/2009/NR-09-05-05.html  |archive-url=https://web.archive.org/web/20100527184853/https://publicaffairs.llnl.gov/news/news_releases/2009/NR-09-05-05.html |archive-date=May 27, 2010 |access-date=September 13, 2009 |publisher=[[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]]}}</ref> The first laser shots into a hohlraum target were fired in late June.<ref name="firstshots" />

==== Buildup to main experiments, 2010 ====
On January 28, 2010, NIF reported the delivery of a 669 kJ pulse to a gold [[Physics:Hohlraum|hohlraum]], breaking records for laser power delivery, and analysis suggested that suspected interference by generated plasma would not be a problem in igniting a fusion reaction.<ref name="Palmer">{{cite news |url=http://news.bbc.co.uk/2/hi/science/nature/8485669.stm |title=Laser fusion test results raise energy hopes |work=BBC News |author=Jason Palmer |date=January 28, 2010 |access-date=January 28, 2010}}</ref><ref name="Seaver">{{cite web |url=https://publicaffairs.llnl.gov/news/news_releases/2010/NR-10-01-06.html |title=Initial NIF experiments meet requirements for fusion ignition |publisher=[[Organization:Lawrence Livermore National Laboratory|Lawrence Livermore National Laboratory]] |date=January 28, 2010 |access-date=January 28, 2010  |archive-url=https://web.archive.org/web/20100527171341/https://publicaffairs.llnl.gov/news/news_releases/2010/NR-10-01-06.html |archive-date=May 27, 2010}}</ref> Due to the size of the test hohlraums, laser/plasma interactions produced plasma-optics gratings, acting like tiny prisms, which produced symmetric X-ray drive on the capsule inside the hohlraum.<ref name="Seaver" />

After gradually altering the wavelength of the laser, scientists compressed a spherical capsule evenly and heated it to 3.3 million [[Kelvin|kelvin]]s (285 eV).<ref name="Bullis" /> The capsule contained cryogenically cooled gas, acting as a substitute for the [[Physics:Deuterium|deuterium]] and [[Physics:Tritium|tritium]] fuel capsules to be used later.<ref name="Seaver" /> Plasma Physics Group Leader Siegfried Glenzer said that they could maintain the precise fuel layers needed in the lab, but not yet within the laser system.<ref name="Bullis">{{cite magazine |url=http://www.technologyreview.com/blog/energy/24720/ |title=Scientists Overcome Obstacle to Fusion |last=Bullis |first=Kevin |date=January 28, 2010 |magazine=Technology Review |access-date=January 29, 2010}}</ref>

As of January 2010, the NIF reached 1.8 megajoules. The target chamber then needed to be equipped with shields to block neutrons.<ref name="Palmer" />

==== National Ignition Campaign 2010–2012 ====
[[File:Worker inside the target chamber of the National Ignition Facility.jpg|thumb|Technician works on target positioner inside National Ignition Facility (NIF) target chamber.]]
With the main construction complete, NIF started its National Ignition Campaign (NIC) to reach ignition. At the time, articles appeared in science magazines stating that ignition was imminent. ''Scientific American'' opened a 2010 review article with the statement "Ignition is close now. Within a year or two..."<ref>{{cite magazine |last=Moyer |first=Michael |date=March 2010 |title=Fusion's False Dawn |url=https://www.scientificamerican.com/article/fusions-false-dawn/ |magazine=Scientific American |pages=50–57}}</ref>

The first test was carried out on October 8, 2010, at slightly over 1&nbsp;MJ. However, problems slowed the drive toward ignition-level laser energies in the 1.4–1.5 MJ range.{{cn|date=January 2023}}

One problem was the potential for damage from overheating due to a greater concentration of energy on optical components.<ref>{{cite magazine |url=http://www.scientificamerican.com/article.cfm?id=superlaser-national-ignition-facility |title=Superlaser fires a blank |author=Eugenie Samuel Reich |date=October 18, 2010 |magazine=Scientific American |access-date=October 2, 2010}}</ref> Other issues included problems layering the fuel inside the target, and minute quantities of dust on the capsule surface.<ref name="kramerreview">{{Cite web |last=Kramer |first=David |date=April 21, 2011 |title=NIF overcomes some problems, receives mixed review from its DOE overseer |url=http://blogs.physicstoday.org/politics/2011/04/drive-for-fusion-milestone-ove.html  |archive-url=https://web.archive.org/web/20110430001208/http://blogs.physicstoday.org/politics/2011/04/drive-for-fusion-milestone-ove.html |archive-date=April 30, 2011 |publisher=Physics Today}}</ref>

The power level continued to increase and targets became more sophisticated. Then minute amounts of water vapor appeared in the target chamber and froze to the windows on the ends of the hohlraums, causing an asymmetric implosion. This was solved by adding a second layer of glass on either end, in effect creating a storm window.<ref name="kramerreview" />

Shots halted from February to April 2011, to conduct SSMP materials experiments. Then, NIF was upgraded, improving diagnostic and measurement instruments. The Advanced Radiographic Capability (ARC) system was added, which uses 4 of the NIF's 192 beams as a backlight for imaging the implosion sequence. ARC is essentially a petawatt-class laser with peak power exceeding a quadrillion (10<sup>15</sup>) watts. It is designed to produce brighter, more penetrating, higher-energy x rays. ARC became the world's highest-energy short-pulse laser, capable of creating picosecond-duration laser pulses to produce energetic x rays in the range of 50–100 keV.<ref>{{cite web |url=https://lasers.llnl.gov/news/photons-fusion/2014/may |title=Photons & Fusion Newsletter – May 2014 |author=<!--Staff writer(s); no by-line.--> |date=May 2014 |website=National Ignition Facility & Photon Science News – Archive – Photons & Fusion Newsletter |publisher=Lawrence Livermore National Laboratory |access-date=April 16, 2015}}</ref>

NIC runs restarted in May 2011 with the goal of more precisely timing the four laser shock waves that compress the fusion target.{{cn|date=January 2023}}

In January 2012, Mike Dunne, director of NIF's laser fusion energy program, predicted that ignition would be achieved at NIF by October.<ref>{{cite web |author=SPIE Europe Ltd |url=http://optics.org/news/3/1/37 |title=PW 2012: fusion laser on track for 2012 burn |publisher=Optics.org |access-date=October 8, 2012}}</ref> In the same month, the NIF fired a record high 57 shots.<ref name="nature201203">{{cite journal |date=March 7, 2012 |title=Laser fusion nears crucial milestone |volume=483 |issue=7388 |pages=133–134 |author=Eric Hand |journal=Nature |doi=10.1038/483133a |pmid=22398531 |bibcode=2012Natur.483..133H |doi-access=free}}</ref> On March 15 NIF produced a laser pulse with 411 TW of peak power.<ref>{{Cite news |url=https://www.theregister.co.uk/2012/03/23/nif_laser_pulse/ |title=Record-breaking laser pulse raises fusion-power hopes |access-date=March 22, 2012 |date=March 22, 2012}}</ref> On July 5, it produced a shorter pulse of 1.85 MJ and increased power of 500 TW.<ref>{{Cite web |url=https://www.foxnews.com/science/worlds-most-powerful-laser-fires-most-powerful-laser-blast-ever |title=World's most powerful laser fires most powerful laser blast ever |date=March 27, 2015 |website=Fox News}}</ref>

=== DOE Report, July 19, 2012 ===
NIC was periodically reviewed. The 6th review, was published on July 19, 2012.<ref name="Crandall">{{cite web |url=http://fire.pppl.gov/NIF_NIC_report_rev5_koonin_2012.pdf |title=External Review of the National Ignition Campaign |publisher=[[Organization:Princeton Plasma Physics Laboratory|Princeton Plasma Physics Laboratory]]}}</ref> The report praised the quality of the installation: lasers, optics, targets, diagnostics, and operations. However:
:The integrated conclusion based on this extensive period of experimentation, however, is that considerable hurdles must be overcome to reach ignition or the goal of observing unequivocal alpha heating. Indeed the reviewers note that given the unknowns with the present 'semi-empirical' approach, the probability of ignition before the end of December is extremely low and even the goal of demonstrating unambiguous alpha heating is challenging.<ref name="Crandall" />{{Rp|page=2}}

Further, the report expressed deep concerns that the gaps between observed performance and simulation codes implied that the current codes were of limited utility. Specifically, they found a lack of predictive ability of the radiation drive to the capsule and inadequately modeled laser–plasma interactions. Pressure was reaching only one half to one third of that required for ignition, far below the predicted values. The memo discussed the mixing of ablator material and capsule fuel likely due to hydrodynamics instabilities in the ablator's outer surface.<ref name="Crandall" />

The report suggested using a thicker ablator, although this would increase its inertia. To keep the required implosion speed, they proposed that the NIF energy be increased to 2MJ. It questioned whether or not the energy was sufficient to compress a large enough capsule to avoid the mix limit and reach ignition.{{sfn|Crandall|2012|p=5}} The report concluded that ignition within the calendar year 2012 was 'highly unlikely'.<ref name="Crandall" />

NIC officially ended on September 30, 2012. Media reports suggested that NIF would shift its focus toward materials research.<ref>{{cite journal |first=Geoff |last=Brumfiel |url=http://www.scientificamerican.com/article.cfm?id=worlds-most-powerful-laser-facility-shifts-focus-to-warheads |title=World's Most Powerful Laser Facility Shifts Focus to Warheads |journal=Scientific American |date=November 7, 2012}}</ref><ref>{{cite journal |journal=Nature |volume=491 |issue=7423 |page=159 |title=Editorial: Ignition switch |date=November 7, 2012 |doi=10.1038/491159a |pmid=23139940 |doi-access=free}}</ref>

In 2008, LLNL began the [[Engineering:Laser Inertial Fusion Energy|Laser Inertial Fusion Energy]] program (LIFE), to explore ways to use NIF technologies as the basis for a commercial power plant design. The focus was on pure fusion devices, incorporating technologies that developed in parallel with NIF that would greatly improve the performance of the design.<ref name="endslife" /> In April 2014, LIFE ended.<ref name="endslife">{{cite journal |title=Livermore Ends LIFE |journal=Physics Today |volume=67 |issue=4 |pages=26–27 |date=April 2014 |first=David |last=Kramer |doi=10.1063/PT.3.2344 |bibcode=2014PhT....67R..26K |s2cid=178876869 }}</ref>

=== Fuel gain breakeven, 2013 ===
A NIF fusion shot on September 27, 2013, produced more energy than was absorbed by the [[Physics:Deuterium–tritium fusion|deuterium–tritium]] fuel.<ref name=":2">{{Cite journal |last1=Hurricane |first1=O. A. |last2=Callahan |first2=D. A. |last3=Casey |first3=D. T. |last4=Celliers |first4=P. M. |last5=Cerjan |first5=C. |last6=Dewald |first6=E. L. |last7=Dittrich |first7=T. R. |last8=Döppner |first8=T. |last9=Hinkel |first9=D. E. |last10=Hopkins |first10=L. F. Berzak |last11=Kline |first11=J. L. |last12=Le Pape |first12=S. |last13=Ma |first13=T. |last14=MacPhee |first14=A. G. |last15=Milovich |first15=J. L. |date=February 2014 |title=Fuel gain exceeding unity in an inertially confined fusion implosion |url=https://www.nature.com/articles/nature13008 |journal=Nature |language=en |volume=506 |issue=7488 |pages=343–348 |doi=10.1038/nature13008 |pmid=24522535 |bibcode=2014Natur.506..343H |s2cid=4466026 |issn=1476-4687}}</ref> This has been confused with having reached "[[Physics:Fusion energy gain factor|scientific breakeven]]",<ref>{{cite web |last=Clery |first=Daniel |date=October 10, 2013 |title=Fusion "Breakthrough" at NIF? Uh, Not Really |url=http://news.sciencemag.org/physics/2013/10/fusion-breakthrough-nif-uh-not-really-%E2%80%A6 |website=ScienceInsider}}</ref><ref>{{cite web |last=Hecht |first=Jeff |date=October 9, 2013 |title=Progress at NIF, but no 'breakthrough' |url=http://www.laserfocusworld.com/articles/2013/10/progress-at-nif-but-no-breakthrough.html |website=LaserFocusWorld}}</ref>  defined as the fusion energy exceeding the laser input energy.<ref name="scibr">{{cite web |last=Meade |first=Dale |date=October 11, 2013 |title=Scientific Breakeven for Fusion Energy |url=http://fire.pppl.gov/ICF_Scientific_Breakeven_LLNL2.pdf}}</ref> Using this definition gives 14.4&nbsp;kJ out and 1.8&nbsp;MJ in, a ratio of 0.008.<ref name=":2" />

=== Stockpile experiments, 2013–2015 ===
In 2013, NIF shifted focus to materials and weapons research. Experiments beginning in FY 2015 used plutonium targets.<ref>{{cite news |first=Jeremy |last=Thomas |url=http://www.contracostatimes.com/my-town/ci_27426991/despite-objections-lawrence-livermore-lab-go-forward-plutonium |title=Despite objections, Livermore lab to fire world's largest laser at plutonium |newspaper=Contra Cost Times |date=January 30, 2014}}</ref> Plutonium shots simulate the compression of the primary in a nuclear bomb by high explosives, which had not seen direct testing since CNTB took effect. Plutonium use ranged from less than a milligram to 10 milligrams.<ref name="pumercury">{{cite news |last=Thomas |first=Jeremy |date=December 12, 2014 |title=Lawrence Livermore National Lab to test plutonium using NIF laser |newspaper=San Jose Mercury News |url=http://www.mercurynews.com/education/ci_27119177/lawrence-livermore-lab-test-plutonium-using-nif-laser}}</ref>

In FY 2014, NIF performed 191 shots, slightly more than one every two days. As of April 2015 NIF was on track to meet its goal of 300 laser shots in FY 2015.<ref>{{cite web |url=https://lasers.llnl.gov/news/efficiency-improvements |title=NIF Lasers Continue to Fire at a Record Rate |website=LLNL}}</ref>

=== Back to fusion, 2016–present ===
On January 28, 2016, NIF successfully executed its first gas pipe experiment intended to study the absorption of large amounts of laser light within {{convert|1|cm}} long targets relevant to high-gain [[Physics:Magnetized liner inertial fusion|magnetized liner inertial fusion]] (MagLIF). In order to investigate key aspects of the propagation, stability, and efficiency of laser energy coupling at full scale for high-gain MagLIF target designs, a single quad of NIF was used to deliver 30 kJ of energy to a target during a 13 nanosecond shaped pulse. Data return was favorable.<ref>{{Cite web |title=Experimental Highlights – 2016 |url=https://lasers.llnl.gov/news/experimental-highlights/2016/january |access-date=December 14, 2022 |website=lasers.llnl.gov}}</ref>

In 2018, improvements in controlling compression asymmetry was demonstrated in a shot with an output of 1.9×10<sup>16</sup> neutrons, resulting in 0.054 MJ of fusion energy released by a 1.5 MJ laser pulse.<ref>{{cite journal |last1=Le Pape |first1=S. |last2=Berzak Hopkins |first2=L. F. |last3=Divol |first3=L. |last4=Pak |first4=A. |last5=Dewald |first5=E. L. |last6=Bhandarkar |first6=S. |last7=Bennedetti |first7=L. R. |last8=Bunn |first8=T. |last9=Biener |first9=J. |last10=Crippen |first10=J. |last11=Casey |first11=D. |last12=Edgell |first12=D. |last13=Fittinghoff |first13=D. N. |last14=Gatu-Johnson |first14=M.|author14-link=Maria Gatu Johnson |last15=Goyon |first15=C. |last16=Haan |first16=S. |last17=Hatarik |first17=R. |last18=Havre |first18=M. |last19=Ho |first19=D. D-M. |last20=Izumi |first20=N. |last21=Jaquez |first21=J. |last22=Khan |first22=S. F. |last23=Kyrala |first23=G. A. |last24=Ma |first24=T. |last25=Mackinnon |first25=A. J. |last26=MacPhee |first26=A. G. |last27=MacGowan |first27=B. J. |last28=Meezan |first28=N. B. |last29=Milovich |first29=J. |last30=Millot |first30=M. |last31=Michel |first31=P. |last32=Nagel |first32=S. R. |last33=Nikroo |first33=A. |last34=Patel |first34=P. |last35=Ralph |first35=J. |last36=Ross |first36=J. S. |last37=Rice |first37=N. G. |last38=Strozzi |first38=D. |last39=Stadermann |first39=M. |last40=Volegov |first40=P. |last41=Yeamans |first41=C. |last42=Weber |first42=C. |last43=Wild |first43=C. |last44=Callahan |first44=D. |last45=Hurricane |first45=O. A. |title=Fusion Energy Output Greater than the Kinetic Energy of an Imploding Shell at the National Ignition Facility |journal=Physical Review Letters |date=June 14, 2018 |volume=120 |issue=24 |page=245003 |doi=10.1103/PhysRevLett.120.245003 |pmid=29956968 |bibcode=2018PhRvL.120x5003L |hdl=1721.1/116411 |doi-access=free}}</ref>

=== Burning plasma achieved, 2021 ===
[[File:NIF output over 10 years.png|upright=1.5|thumb|alt=Plot of NIF results from 2011 to 2021|Plot of NIF results from 2011 to 2021 shows the dramatic increase in fusion energy due to a burning plasma]]
On August 8, 2021, an experiment yielded the world's first [[Astronomy:Burning plasma|burning plasma]].<ref name=":0">{{Cite journal |last1=Zylstra |first1=A. B. |last2=Hurricane |first2=O. A. |last3=Callahan |first3=D. A. |last4=Kritcher |first4=A. L. |last5=Ralph |first5=J. E. |last6=Robey |first6=H. F. |last7=Ross |first7=J. S. |last8=Young |first8=C. V. |last9=Baker |first9=K. L.|last10=Casey|first10=D. T. |last11=Döppner |first11=T. |date=2022 |title=Burning plasma achieved in inertial fusion |journal=Nature |volume=601 |issue=7894 |pages=542–548 |doi=10.1038/s41586-021-04281-w |pmid=35082418 |pmc=8791836 |bibcode=2022Natur.601..542Z |issn=1476-4687}}</ref> The yield was estimated to be 70% of the laser input energy. It produced excess neutrons consistent with a short-lived chain reaction of around 100 trillionths of a second.<ref>{{Cite news |last=Ball |first=Philip |title=U.S. Project Reaches Major Milestone toward Practical Fusion Power |url=https://www.scientificamerican.com/article/u-s-project-reaches-major-milestone-toward-practical-fusion-power/ |access-date=February 11, 2022 |website=Scientific American |language=en}}</ref> The material of the capsule shell was changed to diamond to increase the absorbance of secondary x-rays created by the laser burst, thus increasing the efficacy of the collapse, and its surface was further smoothed. The size of the hole in the capsule used to inject fuel was reduced. The holes in the gold cylinder surrounding the capsule were shrunk to reduce energy loss. The laser pulse was extended.<ref>{{Cite web |last=Clery |first=Daniel |date=August 17, 2021 |title=With explosive new result, laser-powered fusion effort nears 'ignition' |url=https://www.science.org/content/article/explosive-new-result-laser-powered-fusion-effort-nears-ignition |access-date=August 18, 2021 |website=Science |publisher=AAAS |language=en}}</ref> This result slightly beat the former record of 67% set by the [[Physics:Joint European Torus|JET]] torus in 1997.<ref>{{Cite news |url=https://www.nytimes.com/2021/08/17/science/lasers-fusion-power-watts-earth.html |title=Laser Fusion Experiment Unleashes an Energetic Burst of Optimism |first=Kenneth |last=Chang |date=August 17, 2021 |archive-url=https://web.archive.org/web/20210817201327/https://www.nytimes.com/2021/08/17/science/lasers-fusion-power-watts-earth.html |archive-date=August 17, 2021 |newspaper=The New York Times |access-date=August 18, 2021}}</ref> {{Failed verification|date=December 2022}} These numbers are the ratio of energy created by fusion against the amount of energy reaching the plasma. This is not the same as overall power in to power out. The experiment used ~477 MJ of electrical energy to get ~1.8 MJ of energy into the target to create ~1.3 MJ of fusion energy.<ref name=":0" />

An exact year later, on August 8, 2022, three new studies were published confirming the ignition of the plasma under the [[Physics:Lawson criterion|Lawson criterion]] in the original experiment.<ref>{{Cite journal |last1=Indirect Drive ICF Collaboration |last2=Abu-Shawareb |first2=H. |last3=Acree |first3=R. |last4=Adams |first4=P. |last5=Adams |first5=J. |last6=Addis |first6=B. |last7=Aden |first7=R. |last8=Adrian |first8=P. |last9=Afeyan |first9=B. B. |last10=Aggleton |first10=M. |last11=Aghaian |first11=L. |last12=Aguirre |first12=A. |last13=Aikens |first13=D. |last14=Akre |first14=J. |last15=Albert |first15=F. |date=August 8, 2022 |title=Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment |url=https://link.aps.org/doi/10.1103/PhysRevLett.129.075001 |journal=Physical Review Letters |volume=129 |issue=7 |page=075001 |doi=10.1103/PhysRevLett.129.075001 |pmid=36018710 |bibcode=2022PhRvL.129g5001A |hdl=10044/1/99300 |s2cid=250321131|hdl-access=free }}</ref><ref>{{Cite journal |last1=Kritcher |first1=A. L. |last2=Zylstra |first2=A. B. |last3=Callahan |first3=D. A. |last4=Hurricane |first4=O. A. |last5=Weber |first5=C. R. |last6=Clark |first6=D. S. |last7=Young |first7=C. V. |last8=Ralph |first8=J. E. |last9=Casey |first9=D. T. |last10=Pak |first10=A. |last11=Landen |first11=O. L. |last12=Bachmann |first12=B. |last13=Baker |first13=K. L. |last14=Berzak Hopkins |first14=L. |last15=Bhandarkar |first15=S. D. |date=August 8, 2022 |title=Design of an inertial fusion experiment exceeding the Lawson criterion for ignition |journal=Physical Review E |volume=106 |issue=2 |page=025201 |doi=10.1103/PhysRevE.106.025201 |pmid=36110025 |bibcode=2022PhRvE.106b5201K |s2cid=251457864|doi-access=free }}</ref><ref>{{Cite journal |last1=Zylstra |first1=A. B. |last2=Kritcher |first2=A. L. |last3=Hurricane |first3=O. A. |last4=Callahan |first4=D. A. |last5=Ralph |first5=J. E. |last6=Casey |first6=D. T. |last7=Pak |first7=A. |last8=Landen |first8=O. L. |last9=Bachmann |first9=B. |last10=Baker |first10=K. L. |last11=Berzak Hopkins |first11=L. |last12=Bhandarkar |first12=S. D. |last13=Biener |first13=J. |last14=Bionta |first14=R. M. |last15=Birge |first15=N. W. |date=August 8, 2022 |title=Experimental achievement and signatures of ignition at the National Ignition Facility |url=https://link.aps.org/doi/10.1103/PhysRevE.106.025202 |journal=Physical Review E |volume=106 |issue=2 |page=025202 |doi=10.1103/PhysRevE.106.025202 |pmid=36109932 |bibcode=2022PhRvE.106b5202Z |s2cid=251451927}}</ref><ref>{{Cite web |last=Laboratory |first=Lawrence Livermore National |date=August 14, 2022 |title=Nuclear Fusion Energy Breakthrough: Ignition Confirmed in Record 1.3 Megajoule Shot |url=https://scitechdaily.com/nuclear-fusion-energy-breakthrough-ignition-confirmed-in-record-1-3-megajoule-shot/ |access-date=August 14, 2022 |website=SciTechDaily }}</ref>

=== Scientific breakeven achieved, 2022 {{anchor|Achieving ignition}} ===
[[File:National Ignition Facility achieves fusion ignition.webm|thumb|A December 13, 2022 video announcement of the first controlled fusion experiment in history to achieve fusion ignition, via the YouTube page of the Lawrence Livermore National Laboratory]]
[[File:National Ignition Facility Breakeven press conference.png|thumb|Principal designer Annie Kritcher speaks at the December 13, 2022 press conference announcing breakeven ignition.]]

The NIF became the first fusion experiment to achieve [[Physics:Fusion energy gain factor#Scientific breakeven at NIF|scientific breakeven]] on December 5, 2022, with an experiment producing 3.15 megajoules of energy from a 2.05 megajoule input of laser light for an energy gain of about 1.5.<ref name="igntion2022-llnl">{{Cite web |title=National Ignition Facility achieves fusion ignition |url=https://www.llnl.gov/news/national-ignition-facility-achieves-fusion-ignition |access-date=December 13, 2022 |website=www.llnl.gov |language=en}}</ref><ref>{{Cite web |title=DOE National Laboratory Makes History by Achieving Fusion Ignition |url=https://www.energy.gov/articles/doe-national-laboratory-makes-history-achieving-fusion-ignition |access-date=December 13, 2022 |website=Energy.gov |language=en}}</ref><ref>{{cite news |newspaper=The New York Times |title=Scientists Achieve Nuclear Fusion Breakthrough With Blast of 192 Lasers |author=Kenneth Chang |date=December 13, 2022 |url=https://www.nytimes.com/2022/12/13/science/nuclear-fusion-energy-breakthrough.html}}</ref><ref>{{cite web |last1=Bush |first1=Evan |last2=Lederman |first2=Josh |date=December 13, 2022 |title=We have 'ignition': Fusion breakthrough draws energy gain |url=https://www.nbcnews.com/science/science-news/fusion-breakthrough-net-energy-gain-rcna61326 |access-date=December 13, 2022 |website=NBC News}}</ref> Charging the laser consumed "well above 400 megajoules".<ref>{{Cite web|url=https://www.cnet.com/science/major-energy-breakthrough-milestone-achieved-in-us-fusion-experiment/|title=Major Energy Breakthrough: Milestone Achieved in US Fusion Experiment|first=Jackson|last=Ryan|website=CNET}}</ref> In a public announcement on December 13, the Secretary of Energy Jennifer Granholm announced the facility had achieved ignition.<ref>{{cite news |last=Woodward |first=Aylin |date=December 13, 2022 |title=Nuclear-Fusion Energy Breakthrough Reported by Scientists at U.S. Lab |publisher={{wipe|The Wall Street Journal}} |url=https://www.wsj.com/articles/nuclear-fusion-energy-breakthrough-reported-by-scientists-at-u-s-lab-11670944595?mod=hp_lead_pos10}}</ref>

The feat required the use of a slightly thicker and smoother capsule surrounding the fuel and a 2.05 MJ laser (up from 1.9 MJ in 2021), yielding 3.88 MJ, an 89% surplus.<ref>{{Cite journal |url=https://www.science.org/content/article/news-glance-more-success-fusion-medical-tests-under-scrutiny-and-grizzly-reintroduction |title= Fusion update|journal=Science}}</ref> They also redistributed the energy among the split laser beams, which produced a more symmetrical (spherical) implosion.<ref name=":1" />

The NIF achieved breakeven for a second time on July 30, 2023.<ref name= repeatOn30jul2023 >Lavanya Ahire in Bengaluru and Doina Chiacu in Washington, Reuters [https://news.yahoo.com/us-scientists-repeat-fusion-power-195334524.html (7 Aug 2023) US scientists repeat fusion ignition breakthrough for 2nd time]</ref> At least three of five shots achieved breakeven in 2023. These successes led the DOE to fund three additional research centers.<ref>{{Cite journal |last=Tollefson |first=Jeff |date=2023-12-15 |title=US nuclear-fusion lab enters new era: achieving ‘ignition’ over and over |url=https://www.nature.com/articles/d41586-023-04045-8 |journal=Nature |language=en |doi=10.1038/d41586-023-04045-8}}</ref> Lawrence Livermore planned to raise laser energy to 2.2 MJ per shot through upgraded optics and lasers {{circa|2023}}.<ref>{{cite news|newspaper=The New York Times|title=A Laser Fusion Breakthrough Gets a Bigger Burst of Energy|author=Kenneth Chang|date=September 25, 2023|url=https://www.nytimes.com/2023/09/25/science/nuclear-laser-fusion-nif.html}}</ref><ref>{{cite web|title=FY 2022 Annual Report National Ignition Facility - 2022|publisher=Lawrence Livermore National Laboratory|access-date=September 26, 2023|url= https://annual.llnl.gov/fy-2022/national-ignition-facility-2022}}</ref>

== Similar projects ==
Some similar experimental ICF projects are:
{{colbegin}}
* [[Engineering:Laser Mégajoule|Laser Mégajoule]] (LMJ)<ref>{{cite web |title=HiPER |url=http://www-lmj.cea.fr/ |publisher=LMF Project |date=2009 |access-date=June 2, 2010}}</ref>
* [[Engineering:Nike laser|Nike laser]]
* [[Engineering:HiPER|High Power laser Energy Research facility]] (HiPER)<ref>{{cite web |title=HiPER |url=http://www.hiper-laser.org/ |publisher=HiPER Project |date=2009 |access-date=May 29, 2009}}</ref>
* [[Organization:Laboratory for Laser Energetics|Laboratory for Laser Energetics]] (LLE)
* [[Physics:Magnetized liner inertial fusion|Magnetized liner inertial fusion]] (MagLIF)<ref>{{cite web |title=Dry-Run Experiments Verify Key Aspect of Nuclear Fusion Concept: Scientific 'Break-Even' or Better Is Near-Term Goal |url=https://www.sciencedaily.com/releases/2012/09/120917124210.htm |access-date=September 24, 2012}}</ref>
* Shenguang-II High Power Laser<ref>{{cite web |title=Shenguang-II High Power Laser |url=http://caod.oriprobe.com/articles/10880138/Shenguang__%E2%85%A1__High_Power_Laser_Facility.htm |publisher=Chinese Academy of Sciences |access-date=June 12, 2014}}</ref>
{{colend}}

== Pictures ==
<gallery mode="packed" heights="150px">
File:Viewing port.jpg|Viewing port allows a look into the interior of the 30 foot diameter target chamber.
File:NIF target chamber exterior.jpg|Exterior view of the upper third of the target chamber. The large square beam ports are prominent.
File:National Ignition Facility diagnostic handling instrument.jpg|A technician loads an instrument canister into the vacuum-sealed diagnostic instrument manipulator.
File:nif flashlamps.jpg|The flashlamps used to pump the main amplifiers are the largest ever in commercial production.
File:Laser glass slabs.jpg|The glass slabs used in the amplifiers are likewise much larger than those used in previous lasers.
</gallery>

== In popular culture ==
The NIF was used as the set for the starship ''Enterprise'''s warp core in the 2013 movie ''Star Trek Into Darkness''.<ref>{{cite web |last1=Bishop |first1=Breanna |title=National Ignition Facility provides backdrop for "Star Trek: Into Darkness" |url=https://www.llnl.gov/news/national-ignition-facility-provides-backdrop-star-trek-darkness |website=Lawrence Livermore National Laboratory |access-date=November 19, 2015}}</ref>

== See also ==
{{colbegin}}
*[[Organization:Z Pulsed Power Facility|Z Pulsed Power Facility]]
*[[Philosophy:Chain reaction|Chain reaction]]
*[[Engineering:HiPER|HiPER]]
*[[Physics:Inertial confinement fusion|Inertial confinement fusion]]
*[[Organization:ITER|ITER]]
*[[Engineering:Laser Mégajoule|Laser Mégajoule]]
*[[Physics:Nuclear fusion|Nuclear fusion]]
*[[Physics:Nuclear reactor|Nuclear reactor]]
{{colend}}

== Notes ==
{{notelist}}

== References ==
{{Reflist}}

== External links ==
*{{Cite web |date=May 27, 2010 |title=National Ignition Facility: How NIF Works, NIF & Photon Science |url=https://lasers.llnl.gov/about/nif/how_nif_works/index.php |access-date=December 5, 2020 |archive-url=https://web.archive.org/web/20100527152319/https://lasers.llnl.gov/about/nif/how_nif_works/index.php |archive-date=May 27, 2010}}
*{{Cite web |title=Lasers, Photonics, and Fusion Science: Science and Technology on a Mission |url=https://lasers.llnl.gov/ |access-date=December 5, 2020 |website=lasers.llnl.gov}}
*{{Cite magazine |archive-date=October 2, 2011 |title=NIF Director, Dr Ed Moses, on the progress of the facility |url=http://www.ingenia.org.uk/ingenia/articles.aspx?Index=466 |archive-url=https://web.archive.org/web/20111002145910/http://www.ingenia.org.uk/ingenia/articles.aspx?Index=466 |access-date=December 5, 2020 |magazine=Ingenia |date=December 2007}}
*{{Cite web |title=NIF project director Moses says facility is ready to go |url=https://spie.org/news/0324-nif-to-launch |access-date=December 5, 2020 |website=spie.org}}
*{{Cite web |date=November 13, 2009 |title=Inside Livermore Lab's Race to Invent Clean Energy |url=https://www.newsweek.com/inside-livermore-labs-race-invent-clean-energy-77037 |access-date=December 5, 2020 |website=Newsweek |language=en}}
*{{Cite web |last=Eric |title=NIF Laser Fusion in Fulldome |date=April 10, 2011 |url=http://www.xrez.com/case-studies/nif-laser-fusion-in-fulldome/ |access-date=December 5, 2020 |language=en-US}}
*{{Cite journal |last1=Clery |first1=Daniel |date=November 23, 2020 |title=Laser fusion reactor approaches 'burning plasma' milestone |url=https://www.science.org/content/article/laser-fusion-reactor-approaches-burning-plasma-milestone |access-date=December 5, 2020 |journal=Science |volume=370 |issue=6520 |pages=1019–1020 |doi=10.1126/science.370.6520.1019 |pmid=33243866 |bibcode=2020Sci...370.1019C |s2cid=227182275 |language=en}}
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{{Fusion power}}
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[[Category:Nuclear research institutes]]
[[Category:Engineering projects]]
[[Category:Inertial confinement fusion research lasers]]

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