112:(27 million degrees F). Stars are so large that the fusion products will almost always interact with the plasma before their energy can be lost to the environment at the outside of the star. In comparison, man-made reactors are far less dense and much smaller, allowing the fusion products to easily escape the fuel. To offset this, much higher rates of fusion are required, and thus much higher temperatures; most man-made fusion reactors are designed to work at temperatures over 100 million kelvins (180 million degrees F).
68:
97:, a similar concept that compares the total energy being given off to the energy being used to heat the fuel. The key difference is that breakeven ignores losses to the surroundings, which do not contribute to heating the fuel, and thus are not able to make the reaction self-sustaining. Breakeven is an important goal in the
216:
of fusion energy, an 8-fold improvement on tests done in spring 2021. NIF estimates that the laser supplied 1.9 megajoules of energy, 230 kilojoules of which reached the fuel capsule. This corresponds to a total scientific
40:
more rapidly than it cools. In other words, fusion ignition is the point at which the increasing self-heating of the nuclear fusion removes the need for external heating. This is quantified by the
244:
announced via
Twitter that an experiment on December 5 had surpassed the August result, achieving a scientific gain of 1.5, surpassing the National Academy of Sciences definition of ignition.
212:
in
California reported in 2021 that it had triggered ignition in the laboratory on 8 August 2021, for the first time in the over-60-year history of the ICF program. The shot yielded 1.3
55:, fusion ignition defined by the Lawson criterion was first achieved in August 2021, and ignition defined by the energy gain factor was achieved in December 2022, both by the U.S.
71:
Schematic of the stages of inertial confinement fusion using lasers. The blue arrows represent radiation; orange is blowoff; yellow is inwardly transported thermal energy.
189:
is intended to sustain fusion mostly by internal fusion heating and yield in its plasma a ten-fold return on power. Construction is expected to be completed in 2025.
225:– a total energy gain greater than one – most people working in the field viewed the experiment as the demonstration of ignition as defined by the Lawson criterion.
540:
178:
Director Mike Dunne predicted in a
Photonics West 2012 plenary talk that ignition would be achieved at NIF by October 2012. By 2022 the NIF had achieved ignition.
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The shot at
Lawrence Livermore National Laboratory on 5 December is the first-ever controlled fusion reaction to produce an energy gain.
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241:
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This feat established a scientific energy gain of 1.5, over the gain of 1 used by the
National Academy of Sciences to define ignition
154:
experiments that achieve fusion ignition. This is similar to a thermonuclear weapon, but the
National Ignition Facility uses a 1.8
139:). The fuel reaches high enough pressures and densities to ignite, releasing large amounts of energy and neutrons in the process.
81:
During the final part of the capsule implosion, the fuel core reaches 20 times the density of lead and ignites at 100,000,000 ˚C.
430:
354:
240:. Throughout 2022, the NIF researchers tried and failed to replicate the August result. However, on 13 December 2022, the
75:
Laser beams or laser-produced X-rays rapidly heat the surface of the fusion target, forming a surrounding plasma envelope.
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222:
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laser system instead of a fission weapon to compress the fuel, and uses a much smaller amount of fuel (a mixture of
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831:"Three peer-reviewed papers highlight scientific results of National Ignition Facility record yield shot"
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of 0.7 and a capsule energy gain of 6. While the experiment fell short of ignition as defined by the
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Experts believe that achieving fusion ignition is the first step towards electricity generation using
920:
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Thermonuclear burn spreads rapidly through the compressed fuel, yielding many times the input energy.
228:
In August 2022, the results of the experiment were confirmed in three peer-reviewed papers: one in
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541:"Nuclear fusion reactor reaches 100 Million C for 30 secs. Here's what it means for the future"
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Lawson, J. D. (December 1955). "Some
Criteria for a Power Producing Thermonuclear Reactor".
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607:
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810:"National Ignition Facility experiment puts researchers at threshold of fusion ignition"
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25:
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135:) "sparkplug" to generate high pressures and compress a rod of fusion fuel (usually
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917:"BREAKING NEWS: This is an announcement that has been decades in the making"
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Fuel is compressed by the rocket-like blowoff of the hot surface material.
793:
789:"Major nuclear fusion milestone reached as 'ignition' triggered in a lab"
381:"Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment"
171:
167:
101:
field, but ignition is required for a practical energy producing design.
690:
115:
Fusion ignition was first achieved by humans in the cores of detonating
932:
704:
National
Research Council (U.S.). Plasma Committee (20 December 2007).
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National
Research Council (U.S.). Plasma Committee (20 December 2007).
355:"Ignition gives U.S. 'unique opportunity' to lead world's IFE research"
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In nature, stars reach ignition at temperatures similar to that of the
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132:
128:
109:
33:
467:"National Ignition Facility surpasses long-awaited fusion milestone"
889:"Breakthrough in nuclear fusion could mean 'near-limitless energy'"
510:"The National Ignition Facility: Ushering in a New Age for Science"
155:
124:
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595:
186:
105:
850:"Lawrence Livermore's latest attempts at ignition fall short"
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Plasma
Science: Advancing Knowledge in the National Interest
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Plasma Science: Advancing Knowledge in the National Interest
431:"With historic explosion, a long sought fusion breakthrough"
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Abu-Shawareb, H.; Acree, R.; Adams, P. (8 August 2022).
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665:"PW 2012: fusion laser on track for 2012 burn"
317:Proceedings of the Physical Society, Section B
119:. A thermonuclear weapon uses a conventional
8:
642:. The National Academic Press. p. 24.
479:(2), American Institute of Physics: 1213a,
36:being given off by the reaction heats the
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406:
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572:U.S. Nuclear Weapons: The Secret History
357:. Lawrence Livermore National Laboratory
280:
835:Lawrence Livermore National Laboratory
815:Lawrence Livermore National Laboratory
738:Wright, Katherine (30 November 2021).
514:Lawrence Livermore National Laboratory
290:"New project aims for fusion ignition"
210:Lawrence Livermore National Laboratory
148:Lawrence Livermore National Laboratory
44:. Ignition can also be defined by the
740:"Ignition First in a Fusion Reaction"
91:Ignition should not be confused with
7:
539:Narang, Gaurvi (11 September 2022).
353:Bishop, Breanna (6 February 2023).
887:Davis, Nicola (12 December 2022).
829:Padilla, Michael (8 August 2022).
808:Bishop, Breanna (18 August 2021).
787:Dunning, Hayley (17 August 2021).
429:Clery, Daniel (13 December 2022).
288:Chandler, David L. (10 May 2010).
242:United States Department of Energy
14:
848:Kramer, David (3 December 2021).
663:Hatcher, Mike (26 January 2012).
465:David Kramer (13 December 2022),
710:. The National Academic Press.
398:10.1103/PhysRevLett.129.075001
200:2021 and 2022 ignition reports
1:
915:@energy (13 December 2022).
223:National Academy of Sciences
259:Inertial confinement fusion
152:inertial confinement fusion
989:
950:National Ignition Facility
337:10.1088/0370-1301/70/1/303
269:Timeline of nuclear fusion
206:National Ignition Facility
176:National Ignition Facility
144:National Ignition Facility
57:National Ignition Facility
46:fusion energy gain factor
866:10.1063/PT.6.2.20211203a
485:10.1063/PT.6.2.20221213a
24:is the point at which a
445:10.1126/science.adg2803
231:Physical Review Letters
32:. This occurs when the
16:Term in nuclear physics
765:10.1103/Physics.14.168
150:performs laser-driven
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117:thermonuclear weapons
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185:reactor design, the
174:). In January 2012,
108:, around 15 million
756:2021PhyOJ..14..168W
329:1957PPSB...70....6L
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717:978-0-309-16436-8
649:978-0-309-16436-8
237:Physical Review E
166:, which are both
137:lithium deuteride
28:reaction becomes
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22:Fusion ignition
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958:(in French)
927:14 December
900:13 December
617:10 November
550:28 December
524:26 February
450:13 December
323:(1): 6–10.
300:24 February
234:and two in
219:energy gain
675:11 January
669:Optics.org
391:: 075001.
275:References
214:megajoules
53:laboratory
874:244935714
774:244829710
604:865554459
493:254663644
160:deuterium
94:breakeven
38:fuel mass
967:Category
794:Phys.org
612:2392513M
596:87021995
568:(1988).
545:ThePrint
294:MIT News
248:See also
172:hydrogen
168:isotopes
63:Research
933:Twitter
752:Bibcode
750:: 168.
744:Physics
436:Science
414:26 July
361:26 July
325:Bibcode
208:at the
183:tokamak
164:tritium
121:fission
110:kelvins
51:In the
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129:Pu-239
34:energy
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870:S2CID
770:S2CID
578:Crown
489:S2CID
296:. MIT
125:U-235
929:2022
902:2022
858:2021
712:ISBN
677:2019
644:ISBN
619:2021
600:OCLC
592:LCCN
582:ISBN
552:2022
526:2012
477:2022
452:2022
416:2023
363:2023
302:2012
204:The
187:ITER
162:and
142:The
862:doi
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