List of fusion experiments

The Nova laser, used for inertial confinement fusion experiments from 1984 until decommissioned in 1999.

Experiments directed toward developing fusion power are invariably done with dedicated machines which can be classified according to the principles they use to confine the plasma fuel and keep it hot.

The major division is between magnetic confinement and inertial confinement. In magnetic confinement, the tendency of the hot plasma to expand is counteracted by the Lorentz force between currents in the plasma and magnetic fields produced by external coils. The particle densities tend to be in the range of 7018100000000000000♠10¹⁸ to 7022100000000000000♠10²² m⁻³ and the linear dimensions in the range of 6999100000000000000♠0.1 to 10 m. The particle and energy confinement times may range from under a millisecond to over a second, but the configuration itself is often maintained through input of particles, energy, and current for times that are hundreds or thousands of times longer. Some concepts are capable of maintaining a plasma indefinitely.

In contrast, with inertial confinement, there is nothing to counteract the expansion of the plasma. The confinement time is simply the time it takes the plasma pressure to overcome the inertia of the particles, hence the name. The densities tend to be in the range of 7031100000000000000♠10³¹ to 7033099999999999999♠10³³ m⁻³ and the plasma radius in the range of 1 to 100 micrometers. These conditions are obtained by irradiating a millimeter-sized solid pellet with a nanosecond laser or ion pulse. The outer layer of the pellet is ablated, providing a reaction force that compresses the central 10% of the fuel by a factor of 10 or 20 to 10³ or 7004100000000000000♠10⁴ times solid density. These microplasmas disperse in a time measured in nanoseconds. For a reactor, a repetition rate of several per second will be needed.

Magnetic confinement

Within the field of magnetic confinement experiments, there is a basic division between toroidal and open magnetic field topologies. Generally speaking, it is easier to contain a plasma in the direction perpendicular to the field than parallel to it. Parallel confinement can be solved either by bending the field lines back on themselves into circles or, more commonly, toroidal surfaces, or by constricting the bundle of field lines at both ends, which causes some of the particles to be reflected by the mirror effect. The toroidal geometries can be further subdivided according to whether the machine itself has a toroidal geometry, i.e., a solid core through the center of the plasma. The alternative is to dispense with a solid core and rely on currents in the plasma to produce the toroidal field.

Mirror machines have advantages in a simpler geometry and a better potential for direct conversion of particle energy to electricity. They generally require higher magnetic fields than toroidal machines, but the biggest problem has turned out to be confinement. For good confinement there must be more particles moving perpendicular to the field than there are moving parallel to the field. Such a non-Maxwellian velocity distribution is, however, very difficult to maintain and energetically costly.

The mirrors' advantage of simple machine geometry is maintained in machines which produce compact toroids, but there are potential disadvantages for stability in not having a central conductor and there is generally less possibility to control (and thereby optimize) the magnetic geometry. Compact toroid concepts are generally less well developed than those of toroidal machines. While this does not necessarily mean that they cannot work better than mainstream concepts, the uncertainty involved is much greater.

Somewhat in a class by itself is the Z-pinch, which has circular field lines. This was one of the first concepts tried, but it did not prove very successful. Furthermore, there was never a convincing concept for turning the pulsed machine requiring electrodes into a practical reactor.

The dense plasma focus is a controversial and "non-mainstream" device that relies on currents in the plasma to produce a toroid. It is a pulsed device that depends on a plasma that is not in equilibrium and has the potential for direct conversion of particle energy to electricity. Experiments are ongoing to test relatively new theories to determine if the device has a future.

Toroidal machine

Toroidal machines can be axially symmetric, like the tokamak and the reversed field pinch (RFP), or asymmetric, like the stellarator. The additional degree of freedom gained by giving up toroidal symmetry might ultimately be usable to produce better confinement, but the cost is complexity in the engineering, the theory, and the experimental diagnostics. Stellarators typically have a periodicity, e.g. a fivefold rotational symmetry. The RFP, despite some theoretical advantages such as a low magnetic field at the coils, has not proven very successful.

Tokamak

Device Name	Status	Construction	Operation	Location	Organisation	Major/Minor Radius	B-field	Fusion Power	Purpose	Image
T-3	Shut down	?	1962-?	Moscow	Kurchatov Institute	1 m/0.12 m	2.5 T	-	First tokamak
ORMAK (Oak Ridge tokaMAK)	Shut down		1971-1976	Oak Ridge	Oak Ridge National Laboratory	0.8 m/0.23 m	2.5 T		First to achieve 20 MK plasma temperature
TFR (Tokamak de Fontenay-aux-Roses)	Shut down		1973-1984	Fontenay-aux-Roses	CEA	1 m/0.2 m	6 T	-
T-10 (Tokamak-10)	Shut down		1975-?	Moscow	Kurchatov Institute	1.50 m/0.36 m	4 T	-	Largest tokamak of its time
PLT (Princeton Large Torus)	Shut down		1975-1986	Princeton	Princeton Plasma Physics Laboratory	1.32 m/0.4 m	4 T	-	First to achieve 1 MA plasma current
TEXTOR (Tokamak Experiment for Technology Oriented Research)[1][2]	Shut down	1976-1980	1981-2013	Jülich	Forschungszentrum Jülich	1.75 m/0.47 m	2.8 T	-	Study plasma-wall interactions
TFTR (Tokamak Fusion Test Reactor)[3]	Shut down	1980-1982	1982-1997	Princeton	Princeton Plasma Physics Laboratory	2.4 m/0.8 m	6 T	10.7 MW	Attempted scientific break-even, reached record fusion power and temperature of 510 MK
JET (Joint European Torus)[4]	Operational	1978-1983	1983-	Culham	Culham Centre for Fusion Energy	2.96 m/0.96 m	4 T	16.1MW	Record for fusion output power
Novillo[5][6]	Shut down	NOVA-II	1983-2004	Mexico City	Instituto Nacional de Investigaciones Nucleares	0.23 m/0.06 m	1 T	-	Study plasma-wall interactions
JT-60 (Japan Torus-60)[7]	Shut down		1985-2010	Naka	Japan Atomic Energy Research Institute	3.4 m/1.0 m	4 T		High-beta steady-state operation, highest fusion triple product
DIII-D[8]	Operational	1986[9]	1986-	San Diego	General Atomics	1.67 m/0.67 m	2.2 T	-	Tokamak Optimization
STOR-M (Saskatchewan Torus-Modified)[10]	Operational		1987-	Saskatoon	Plasma Physics Laboratory (Saskatchewan)	0.46 m/0.125 m	1 T	-	Study plasma heating and anomalous transport
T-15	Recycled →T-15MD	1983-1988	1988-1995	Moscow	Kurchatov Institute	2.43 m/0.7 m	3.6 T	-	First superconducting tokamak.
Tore Supra[11]	Recycled →WEST		1988-2011	Cadarache	Département de Recherches sur la Fusion Contrôlée	2.25 m/0.7 m	4.5 T	-	Large superconducting tokamak with active cooling
ADITYA (tokamak)	Operational		1989-	Gandhinagar	Institute for Plasma Research	0.75 m/0.25 m	1.2 T	-
COMPASS (COMPact ASSembly)[12][13]	Operational	1980-	1989-	Prague	Institute of Plasma Physics AS CR	0.56 m/0.23 m	2.1 T
FTU (Frascati Tokamak Upgrade)	Operational		1990-	Frascati	ENEA	0.935 m/0.35 m	8 T	-
START (Small Tight Aspect Ratio Tokamak)[14]	Shut down		1990-1998	Culham	Culham Centre for Fusion Energy	0.3 m/?	0.5 T	-	First full-sized Spherical Tokamak
ASDEX Upgrade (Axially Symmetric Divertor Experiment)	Operational	ASDEX	1991-	Garching	Max-Planck-Institut für Plasmaphysik	1.65 m/0.5 m	2.6 T		Discovery of the H-mode
Alcator C-Mod (Alto Campo Toro)[15]	Shut down	1986-	1991-2016	Cambridge	Massachusetts Institute of Technology	0.68 m/0.22 m	8 T		record plasma pressure 2.05 bar
ISTTOK (Instituto Superior Técnico TOKamak)[16]	Operational		1992-	Lisbon	Instituto de Plasmas e Fusão Nuclear	0.46 m/0.085 m	2.8 T	-
TCV (Tokamak à Configuration Variable)[17]	Operational		1992-	Lausanne	École Polytechnique Fédérale de Lausanne	0.88 m/0.25 m	1.43 T	-	Confinement studies
Pegasus Toroidal Experiment[18]	Operational	?	1996-	Madison	University of Wisconsin–Madison	0.45 m/0.4 m	0.18 T	-	Extremely low aspect ratio
NSTX (National Spherical Torus Experiment)[19]	Operational		1999-	Plainsboro Township	Princeton Plasma Physics Laboratory	0.85 m/0.68 m	0.3 T	-	Study the spherical tokamak concept
ET (Electric Tokamak)	Recycled →ETPD	1998	1999-2006	Los Angeles	UCLA	5 m/1 m	0.25 T	-	Largest tokamak of its time
CDX-U (Current Drive Experiment-Upgrade)	Recycled →LTX		2000-2005	Princeton	Princeton Plasma Physics Laboratory	0.3 m/? m	0.23 T	-	Study Lithium in plasma walls
MAST (Mega-Ampere Spherical Tokamak)[20]	Recycled →MAST-Upgrade	1997-1999	1999-2013	Culham	Culham Centre for Fusion Energy	0.9 m/0.6 m	0.55 T	-	Investigate spherical tokamak for fusion
SST-1 (Steady State Superconducting Tokamak)[21]	Operational	2001-	2005-	Gandhinagar	Institute for Plasma Research	1.1 m/0.2 m	3 T	-	Produce a 1000s elongated double null divertor plasma
EAST (Experimental Advanced Superconducting Tokamak)[22]	Operational	2003-2006	2006-	Hefei	Hefei Institutes of Physical Science	1.85 m/0.4 5m	3.5 T		H-Mode plasma for over 100 s at 50 MK
KSTAR (Korea Superconducting Tokamak Advanced Research)[23]	Operational	1998-2007	2008-	Daejeon	National Fusion Research Institute	1.8 m/0.5 m	3.5 T		Tokamak with fully superconducting magnets
LTX (Lithium Tokamak Experiment)	Operational	2005-2008	2008-	Princeton	Princeton Plasma Physics Laboratory	0.4 m/? m	0.4 T	-	Study Lithium in plasma walls
QUEST (Spherical Tokamak)[24]	Operational		2008-	Kasuga	Kyushu University	0.68 m/0.4 m	0.25 T	-	Study steady state operation of a Spherical Tokamak
Kazakhstan Tokamak for Material testing (KTM)	Operational	2000-2010	2010-	Kurchatov	National Nuclear Center of the Republic of Kazakhstan	0.86 m/0.43 m	1 T	-	Testing of wall and divertor
ST25-HTS	Operational	2012-2015	2015-	Culham	Tokamak Energy Ltd	0.25 m/0.125 m	0.1 T	-	Steady state plasma
WEST (Tungsten Environment in Steady-state Tokamak)	Operational	2013-2016	2016-	Cadarache	Département de Recherches sur la Fusion Contrôlée	2.5 m/0.5 m	3.7 T	-	Superconducting tokamak with active cooling
GLAST III (GLAss Spherical Tokamak)	Operational	2018?	?	Islamabad	Pakistan Atomic Energy Commission	0.2 m/0.1 m	1 T	-	Teaching and Training
ITER[25]	Under construction	2013-	2025?	Cadarache	ITER Council	6.2 m	5.3 T	500 MW ?	demonstrate feasibility of fusion on a power-plant scale
IGNITOR[26]	Planned[27]	?	>2024	Troitzk	ENEA	1.32 m/0.47 m	13 T	100 MW ?	Compact fustion reactor with self-sustained plasma
CFETR (China Fusion Engineering Test Reactor)[28]	Planned	2020?	2030?		Institute of Plasma Physics, Chinese Academy of Sciences	5.7 m ?	5 T ?	1000MW ?	Bridge gaps between ITER and DEMO
K-DEMO (Korean fusion demonstration tokamak reactor)[29]	Planned	2037?			National Fusion Research Institute	6.8 m/2.1 m	7 T	2200 MW ?	Prototype for the development of commercial fusion reactors
DEMO (DEMOnstration Power Station)	Planned	2031?	2044?			7 m		2000 MW	Prototype for a commercial fusion reactor

Stellarator

Device Name	Status	Construction	Operation	Type	Location	Organisation	Major/Minor Radius	B-field	Purpose	Image
Model C	Shut down	1958-1962	1962-1969	Racetrack	Princeton	Princeton Plasma Physics Laboratory	1.2? m/0.07 m	3.5 T	Found large plasma losses by Bohm diffusion
Wendelstein 2-A	Shut down	1965-1968	1968-1974	Heliotron	Garching	Max-Planck-Institut für Plasmaphysik	0.5 m/0.05 m	0.6 T	Good plasma confinement “Munich mystery”
Wendelstein 2-B	Shut down	?-1970	1971-?	Heliotron	Garching	Max-Planck-Institut für Plasmaphysik	0.5 m/0.05 m	1.25 T	Demonstrated similar performance than tokamaks
WEGA	Recycled →HIDRA	?	1975-2013	Classical stellarator	Greifswald	Max-Planck-Institut für Plasmaphysik	0.72 m/0.15 m	1.4 T	Test lower hybrid heating
Wendelstein 7-A	Shut down	?	1975-1985	Classical stellarator	Garching	Max-Planck-Institut für Plasmaphysik	2 m/0.1 m	3.5 T	First "pure" stellarator without plasma current
Wendelstein 7-AS	Shut down	1985-1986	1988-2002	Modular, advanced stellarator	Garching	Max-Planck-Institut für Plasmaphysik	2 m/0.13 m	2.6 T	First H-mode in a stellarator in 1992
H-1NF[30]	Operational		1992-	Heliac	Canberra	Research School of Physical Sciences and Engineering, Australian National University	1.0 m/0.19 m	0.5 T
TJ-K[31]	Operational	TJ-IU	1994-	Torsatron	Kiel, Stuttgart	University of Stuttgart	0.60 m/0.10 m	0.5 T	Teaching
TJ-II[32]	Operational	1991-	1997-	flexible Heliac	Madrid	National Fusion Laboratory, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (Ciemat)	1.5 m/0.28 m	1.2 T	Study plasma in flexible configuration
LHD (Large Helical Device)[33]	Operational	1990-1998	1998-	Heliotron	Toki	National Institute for Fusion Science	3.5 m/0.6 m	3 T	Determine feasibility of a stellarator fusion reactor
HSX (Helically Symmetric Experiment)	Operational		1999-	Modular, quasi-helically symmetric	Madison	University of Wisconsin–Madison	1.2 m/0.15 m	1 T	investigate plasma transport
Uragan-2(M)[34]	?	?	?	Heliotron, Torsatron	Kharkiv	National Science Center, Kharkiv Institute of Physics and Technology (NSC KIPT)	1.7 m/0.24 m	2.4 T	?
Uragan-3 (M)[35]	?	?	?	Heliotron, Torsatron	Kharkiv	National Science Center, Kharkiv Institute of Physics and Technology (NSC KIPT)	1.0 m/0.12 m	1.3 T	?
Columbia Non-neutral Torus (CNT)	Operational	?	2004-	Circular interlocked coils	New York City	Columbia University	0.3 m/0.1 m	0.2 T	Study of non-neutral plasmas
Quasi-poloidal stellarator (QPS)[36][37]	Cancelled	2001-2007	-	Modular	Oak Ridge	Oak Ridge National Laboratory	0.9 m/0.33 m	1.0 T	Stellarator research
NCSX (National Compact Stellarator Experiment)	Cancelled	2004-2008	-	?	Princeton	Princeton Plasma Physics Laboratory	1.4 m/0.32 m	1.7 T	High-β stability
Compact Toroidal Hybrid (CTH)	Operational	?	2007?-	Torsatron	Auburn	Auburn University	0.75 m/0.2 m	0.7 T	Hybrid stellarator/tokamak
HIDRA (Hybrid Illinois Device for Research and Applications)[38]	Operational	2013-2014 (WEGA)	2014-	?	Urbana, IL	University of Illinois at Urbana - Champaign	0.72 m/0.19 m	0.5 T	Stellarator and Tokamak in one device
Wendelstein 7-X[39]	Operational	1996-2015	2015-	Helias	Greifswald	Max-Planck-Institut für Plasmaphysik	5.5 m/0.53 m	3 T	Steady-state plasma in fully optimized stellarator
SCR-1 (Stellarator of Costa Rica)	Operational	2011-2015	2016-	Modular	Cartago	Instituto Tecnológico de Costa Rica	0.14 m/0.042 m	0.044 T

Reversed field pinch (RFP)

• RFX (Reversed-Field eXperiment), Consorzio RFX, Padova, Italy^[40]
• MST (Madison Symmetric Torus), University of Wisconsin–Madison, United States^[41]
• T2R, Royal Institute of Technology, Stockholm, Sweden
• TPE-RX, AIST, Tsukuba, Japan

Magnetic mirror

• Baseball I/Baseball II Lawrence Livermore National Laboratory, Livermore CA.
• TMX, TMX-U Lawrence Livermore National Laboratory, Livermore CA.
• MFTF Lawrence Livermore National Laboratory, Livermore CA.
• Gas Dynamic Trap at Budker Institute of Nuclear Physics, Akademgorodok, Russia.

Spheromak

• Sustained Spheromak Physics Experiment

Field-Reversed Configuration (FRC)

• C-2 Tri Alpha Energy
• C-2U Tri Alpha Energy
• C-3 (under construction?) Tri Alpha Energy
• LSX University of Washington
• IPA University of Washington
• HF University of Washington
• IPA- HF University of Washington

Inertial confinement

Inertial electrostatic confinement

• Fusor
• Polywell

Magnetized target fusion

• FRX-L
• FRCHX
• General Fusion - under development
• LINUS project

References