View source for Magnetized liner inertial fusion

{{Short description|Method of producing controlled nuclear fusion}}
[[File:MagLIF cartoon.svg|thumb|400px|The stages of a MagLIF implosion.{{ordered list
| A laser preheats the fuel.
| An axial current is driven through the liner.
| The current induces an azimuthal magnetic field.
| The magnetic force implodes the liner, compressing and further heating the fuel.}}]]
'''Magnetized liner inertial fusion''' ('''MagLIF''') is an ongoing [[fusion power]] experiment being carried out on the [[Z Pulsed Power Facility]] (Z machine) at [[Sandia National Laboratories]] in the US. It is one example of the broader [[magneto-inertial fusion]] approach, which attempts to compress a pre-heated [[plasma (physics)|plasma]]. The goal is to produce fusion conditions without the level of compression needed in the [[inertial confinement fusion]] (ICF) approach, where the required densities reach about 100 times that of lead.
The term MagLIF may also be used more broadly to refer to machines that use the same operating principle as the one at the Z machine. This includes the Primary Test Stand (PTS) in Mianyang, China.<ref>{{cite journal |last1=Hailong |first1=Zhao |date=12 May 2020 |display-authors=etal |title=Preliminary exploration of MagLIF concept and feasibility analysis on PTS facility |journal=High Power Laser and Particle Beams |volume=32 |issue=6 |pages=62002–62010 |doi=10.11884/HPLPB202032.190352 |url=https://www.hplpb.com.cn/en/article/doi/10.11884/HPLPB202032.190352}}</ref>
==Description==
MagLIF is a method of generating energy by magnetically compressing a cylinder of fusion fuel (such as deuterium). First, an axial magnetic field of 10–20 [[Tesla (unit)|tesla]] is applied to the fuel. Then, a multi-[[kilojoule]] laser shines through the fuel, preheating it to a few million degrees Celsius and turning it into a [[Plasma (physics)|plasma]]. Finally, a 100 [[nanosecond]] pulse of [[electric current]] is driven axially through the metal liner surrounding the fuel. The current induces an intense [[Z-pinch]] magnetic field that [[Implosion (mechanical process)|crushes]] the liner and fuel.
The compression does [[Work (thermodynamics)|work]] to the fuel, heating it to tens of millions of degrees Celsius. Normally the electrons in the plasma would be free to escape, and the ions to a lesser extent, carrying away energy and cooling the plasma. The compression also amplifies the axial magnetic field to thousands of teslas, providing [[magnetic confinement]] to the imploded plasma and trapping the fuel and its heat. Ideally, the plasma reaches a high enough temperature and density to undergo [[Burning plasma|fusion burn]], releasing energy.<ref name="overview">{{cite journal |first1=D. A. |last1=Yager-Elorriaga |first2=M. R. |last2=Gomez |first3=D. E. |last3=Ruiz |first4=S. A. |last4=Slutz |first5=A. J. |last5=Harvey-Thompson |first6=C. A. |last6=Jennings |title=An overview of magneto-inertial fusion on the Z machine at Sandia National Laboratories |journal=Nuclear Fusion |volume=62 |page=042015 |date=2022 |issue=4 |doi=10.1088/1741-4326/ac2dbe |bibcode=2022NucFu..62d2015Y }}</ref>
MagLIF has characteristics of both [[inertial confinement fusion]] (due to the use of a laser and pulsed compression) and [[magnetic confinement fusion]] (due to the use of a powerful magnetic field to inhibit thermal conduction and contain the plasma), making it an example of [[magneto-inertial fusion]].
In results published in 2012, a computer simulation using the LASNEX code showed that a 70&nbsp;megaampere facility would provide an energy yield of 1000 times the expended energy, and a 60&nbsp;megaampere facility would produce a yield of 100 times the expended energy.
==Z Pulsed Power Facility==
[[File:The Z Machine (8056998596).jpg|thumb|300px|The Z machine at Sandia National Labs]]
{{main|Z Pulsed Power Facility}}
[[Sandia National Labs]] is currently exploring the potential for this method to generate energy by utilizing the [[Z Pulsed Power Facility|Z machine]]. The Z machine is capable of 27&nbsp;megaamperes and may be capable of producing slightly more than breakeven energy while helping to validate the computer simulations.<ref>{{cite journal|last=Slutz|first=Stephen|author2=Roger A. Vesey|title=High-Gain Magnetized Inertial Fusion|journal=Physical Review Letters|date=12 January 2012|volume=108|issue=2|doi=10.1103/PhysRevLett.108.025003|bibcode=2012PhRvL.108b5003S|pmid=22324693|page=025003|doi-access=free}}</ref>  The Z-machine conducted MagLIF experiments in November 2013 with a view towards breakeven experiments using D–T fuel in 2018.<ref name="pmid24380935">{{cite journal | author=Gibbs WW | title=Triple-threat method sparks hope for fusion | journal=[[Nature (journal)|Nature]]  | volume=505 | issue=7481 | year=2014 | pages=9–10  | doi = 10.1038/505009a  | pmid=24380935|bibcode = 2014Natur.505....9G | doi-access=free }}</ref>
Sandia Labs planned to proceed to ignition experiments after establishing the following:<ref>{{cite web|title=Dry-Run Experiments Verify Key Aspect of Nuclear Fusion Concept: Scientific 'Break-Even' or Better Is Near-Term Goal|url=http://www.sciencedaily.com/releases/2012/09/120917124210.htm|access-date=24 September 2012}}</ref>
# That the liner will not break apart too quickly under the intense energy. This has been apparently confirmed by recent experiments. This hurdle was the biggest concern regarding MagLIF following its initial proposal.
# That laser preheating is able to correctly heat the fuel&mdash;to be confirmed by experiments starting in December 2012.
# That magnetic fields generated by a pair of coils above and below the hohlraum can serve to trap the preheated fusion fuel and importantly inhibit thermal conduction without causing the target to buckle prematurely&mdash;to be confirmed by experiments starting in December 2012.
Following these experiments, an integrated test started in November 2013. The test yielded about 10<sup>10</sup> high-energy neutrons.
As of November 2013, the facility at Sandia labs had the following capabilities:<ref name="pmid24380935" /><ref>{{cite web|last=Ryan|first=McBride|title=Magnetized LIF and Cylindrical Dynamic Materials Properties Experiments on Z|url=https://www.youtube.com/watch?v=gBtu8S9vAtY|publisher=Krell Institute|access-date=20 November 2013}}</ref>
# 10 tesla magnetic field
# 2 kilojoule laser
# 16 megaamperes
# [[Nuclear fusion#Criteria and candidates for terrestrial reactions|D–D fuel]]
In 2014, the test yielded up to {{val|2|e=12}} D–D neutrons under the following conditions:<ref>{{cite web|last=Gomez|first=M. R.|display-authors=etal| title=Experimental Verification of the Magnetized Liner Inertial Fusion (MagLIF) Concept| url=http://www.krellinst.org/ssgf/conf/2014/video/mgomez| publisher=Krell Institute|access-date=23 May 2015}}</ref>
# 10 tesla magnetic field
# 2.5 kilojoule laser
# 19 megaamperes
# D–D fuel
Experiments aiming for energy breakeven with [[Nuclear fusion#Criteria and candidates for terrestrial reactions|D-T fuel]] were expected to occur in 2018.<ref>{{cite journal|journal=IEEE Transactions on Plasma Science|volume=40|issue=12|pages=3222–3245|last=Cuneo|first=M.E.|display-authors=etal|title=Magnetically Driven Implosions for Inertial Confinement Fusion at Sandia National Laboratories|bibcode=2012ITPS...40.3222C|year=2012|doi=10.1109/TPS.2012.2223488|doi-access=free}}</ref>
<br />
To achieve scientific breakeven, the facility is going through a 5-year upgrade to:
# 30 teslas
# 8 kilojoule laser
# 27 megaamperes
# D–T fuel handling<ref name="pmid24380935" />
In 2019, after encountering significant problems related to mixing of imploding foil with fuel and helical instability of plasma,<ref>{{cite journal |last1=Seyler |first1=C.E. |last2=Martin |first2=M.R. |last3=Hamlin |first3=N.D. |title=Helical instability in MagLIF due to axial flux compression by low-density plasma |journal=Physics of Plasmas |volume=25 |issue=6 |pages=062711 |publisher=Physics of Plasmas 25, 062711 (2018) |doi=10.1063/1.5028365 |year=2018 |bibcode=2018PhPl...25f2711S |osti=1456307 |url=https://www.osti.gov/biblio/1456307 }}</ref> the tests yielded up to 3.2×10<sup>12</sup> neutrons under the following conditions:<ref>{{cite journal|last=Gomez|first=M. R.|display-authors=etal| title=Assessing Stagnation Conditions and Identifying Trends in Magnetized Liner Inertial Fusion|journal=IEEE Transactions on Plasma Science|volume=47|issue=5|pages=2081–2101| publisher=IEEE Transactions on Plasma Science vol. 47/5|doi=10.1109/TPS.2019.2893517|bibcode=2019ITPS...47.2081G|year=2019|osti=1529761|doi-access=free}}</ref>
# 1.2 kilojoule laser
# 18 megaamperes
In 2020, "the burn-averaged ion temperature doubled to 3.1&nbsp;keV and the primary deuterium–deuterium neutron yield increased by more than an order of magnitude to {{val|1.1|e=13}} (2&nbsp;kilojoule deuterium–tritium equivalent) through a simultaneous increase in the applied magnetic field (from 10.4 to 15.9&nbsp;teslas), laser preheat energy (from 0.46 to 1.2&nbsp;kilojoules), and current coupling (from 16 to 20&nbsp;megaamperes)."<ref>{{cite journal |title=Performance Scaling in Magnetized Liner Inertial Fusion Experiments|journal=Phys. Rev. Lett.|publisher=American Physical Society|last=Gomez|first=M. R.|display-authors=etal|volume=125|issue=15|year=2020|pages=155002|doi=10.1103/PhysRevLett.125.155002|pmid=33095639 |bibcode=2020PhRvL.125o5002G |doi-access=free}}</ref>
==See also==
{{portal|Nuclear technology|Energy}}
* [[National Ignition Facility]]
* [[Pinch (plasma physics)]]
* [[Zap Energy]]
==References==
{{Reflist}}
{{Fusion power}}
[[Category:Inertial confinement fusion]]