Spherical Tokamak Table contents

ACST	S Korea Seoul	2000 - 2002	2	0.06	0.02	0.0005	-	-	-	-	AC operation. Helicon plasma discharge.
Asperator T-3	Japan Tohoku	1974 - ?	1.6	0.27	?	0.1
BATORM (BAby TORoidal of Masoud)	Egypt, Cairo	1998	2	0.06	?	?	-	-	-	-	A very small tokamak used for materials testing and tokamak physics studies.
CDX-U Current Drive Experiment	USA, Princeton	1993-2004	1.4	0.3	0.23	0.03	-	-	-	-	FW heating. Now resurrected as the Lithium Tokamak Experiment, LTX.
CPD (Compact Plasma wall interaction Device)	Japan, Kasuga City	Approx. 2007	1.5	0.3	0.3	0.15	0.2	-	-	-	New spherical tokamak at Kyushu University. Only four TF coils, but they are large enough to give a tolerable ripple (8% at r = 0.5m). Includes a thermal lithium beam diagnostic for 2-D density. Also studying non-inductive start-up using ECRH.
ETE (Experimento Tokamak Esférico)	Brazil INPE	2000	1.5	0.3	0.6	0.4	-	-	-	-	Limiter machine
Globus-M	Russia IOFFE	2002 - 2017	1.5	0.36	0.4	0.5	-	1	1.5	-	0.3 second pulses
Globus-M2	Russia IOFFE	2017	1.5	0.36	1	0.5	-	1	1.5	-	Upgraded version of Globus-M with higher toroidal field. Promoting ITER related diagnostics development and material testing and developing of novel program of compact hybrid neutron sources.
GLAST (GLAss Spherical Tokamak)	Pakistan Islamabad	?	1.7	0.15	0.4	0.05	-	-	-	-	MHP model validation and plasma-wall interactions
GUTTA at IOFFE	Russia St Petersburg State University	1980-1985	2	0.16	1.5	0.15	0.03	-	-	-	Russia's first spherical tokamak.
GUTTA (at St Petersburg University)	Russia St Petersburg State University	2004	2	0.16	1.5	0.15	0.03	-	-	-	Formerly operated at IOFFE Institute. Operations restarted 2004 in St Petersburg State University. Start-up and ECRH studies.
HIST	Japan, Himeji	1998	1.3	0.3	0.2	0.1	-	-	-	-
HIT2	USA Seattle	1997-2004	1.5	0.3	0.6	0.37	-	-	-	-	Limiter / single null divertor machine to study Coaxial Helicity Injection (CHI).
HSE (Heidelberg Spheromak Experiment)	Germany Heidelberg	1986-1987	1.1	0.08	0.25	0.1	-	-	-	-	Heidelberg Spheromak Experiment was converted with an axial conductor to a Spherical Tokamak, and operated in this configuration for only a short time, 1986-7. This was the first spherical tokamak experiment at the several kG and 100 kA level. (Spheromak generated by theta-z-pinch method ( equipped with axial conductor. Full diameter of plasma: 0.3m, length of discharge vessel: 1m, Formation of plasma: ~14-20 microseconds, lifetime of plasma after formation: ~40-50 microseconds, magnetic energy content (in plasma ring): 600 J, electron temperature estimate: 15-20 eV.) Thanks to Hardo Bruhns for this information.
KTM Kazakh Tokamak for Material studies	Kazakhstan, Kurchatov	2010	2	0.9	1	0.75		5			Low aspect ratio tokamak for material testing. Will be able to exchange the divertor plates without breaking vacuum. 20 single turn TF coils. Thanks to Alexey Kirilenko for recent information. First plasma September 2010.
LATE Low Aspect ratio Torus Experiment	Japan, Kyoto University	2005	1.25	0.25	0.12	0.004	0.2				Low aspect ratio spherical tokamak for material testing. Will be able to exchange the divertor plates without breaking vacuum. 20 single turn TF coils.
LTX, Lithium Tokamak Experiment	USA, Princeton	2005	1.5	0.4	0.4	0.4	-	-	-	-	Liquid lithium walls. FW heating.
MAST Mega Amp Spherical Tokamak	UK, Culham	1999	1.4	0.85	0.5	1.4	1	-	4	-	Merging compression technique to drive plasma current, saving solenoid flux.
MAST-U Mega Amp Spherical Tokamak Upgrade	UK, Culham	2018	1.4	0.85	0.84	1.4	?	-	5	-	Major upgrade of MAST, with longer pulses, upgraded central column and neutral beam heating, with new 'super-X' divertors. Total heating power rising to 12.5MW.
MEDUSA (Madison EDUcational Small Aspect ratio)	USA Madison	1994 - <2015	1.5	0.12	0.45	0.04	-	-	-	-	Test bed for educational purposes and studies leading to the construction of PEGASUS.
MEDUSA-CR	Costa Rica, Cartago	2016	1.4	0.14	0.5	0.04	-	-	-	-	Recommissioned MEDUSA, moved to Costa Rica Institute of Technology. Test bed for educational purposes and studies of equilibrium and stability between natural divertor D and bean-shaped ST plasmas, study of an ergodic magnetic limiter, Alfvén wave heating and current drive and transport.
NSST Next Step Spherical Torus	USA Princeton	?	?	1.5	2.7	5-10	?	?	?	?	Proposed as the step between today's spherical tokamaks and a large Component Test Facility (CTF). Possibly to use the site that was previously used for TFTR.
NSTX	US Princeton	1999-2010	1.32	0.854	0.55	1	-	6 HHFW	7.5	-	1 second + pulses. In 2009, 94.3 Million USD NSTX Upgrade project was started. See NSTX-U
NSTX-U	US Princeton	2015	1.5	0.934	1.0	2.0	-	6 HHFW	15	-	The upgrade to the original NSTX increased the size and capability of the centerstack and added a second neutral beam. The construction phase began in October 2011. The NSTX-U first plasma was completed in August 2015 successfully concluding the upgrade project. The first experimental run campaign in the new configuration took place in 2016 with 10 run weeks completed by June 30, 2016.
NUCTE-ST	Japan Nihon University	1998	1.2	0.062	0.45	0.34	?	?	?	?	High elongation machine (10).
PEGASUS	USA Madison	1996	1.1 - 1.2	0.2 - 0.45	0.18	0.1 - 0.3		2			Extremely low aspect ratio tokamak. Double null divertor. EBW heating. Studying plasma at extremely high beta, publishing in 2017 that a plasma with beta approaching 100% has been possible, beating the previous record held by START for many years.
Proto-Sphera	Italy Frascati	Soon	?	?	?	?	?	?	?	?	Uses START vacuum vessel.
QUEST (Q-shu University Experiment with steady-state Spherical Tokamak)	Japan, Kasuga City	2008	1.7	0.68	0.25	0.02	?	?	?	?	New spherical tokamak replacing TRIAM-1M. Mission to study issues related to steady-state operation within the All-Japan ST Research Program. In particular, to develop a fully non-inductive current drive scheme that is effective in ST plasmas with high beta and high dielectric constant; to perform integrated studies of recycling and advanced PWI control in steady state, by active control of wall temperature and divertor pumping, and compatibility with high plasma performance; to develop a divertor in ST magnetic configuration which can handle power and particle fluxes in steady state.
Rotamak	Australia Lucas Heights	1987 - 1997	1.1	0.07	0.02	0.003	?	?	?	?	Rotamak with central rod.
Rotamak	Australia Flinders	1998 - 2002	1.6	0.10	0.016	0.012	?	?	?	?	Rotamak with central rod.
SPHEX	UK Manchester	?	1.05	0.23	0.045	0.2					Spheromak, fitted with TF rod in 1991.
ST25	UK Culham Innovation Centre then Milton Park	2012	2	0.25	0.2	0.02	0.003	-	-	-	ST25 stands for Spherical Tokamak major radius 25cm. The term 'ST' is marginal - as it has aspect ratio 2, for reasons explained below. It is formed from copper cable TF , solenoid and PF magnets and powered by a 1.5MJ supercapacitor bank; this combination gives the potential for long pulses - 20s to date (as of 2015). Two 3kW continuous wave magnetrons are used to pre-ionise and study EBW (Electron Bernstein Wave) current drive using an inside-launch port. Unusually, the whole table-top device is contained in a small room and powered from only a 32A 415V supply. Thanks to Alan Sykes of Tokamak Energy for these details.
ST25 HTS	UK Milton Park, Abingdon	2015	2	0.25	0.4 (SC)	TBA	0.003	-	-	-	A new version of ST25 using high-temperature superconducting coils, built by Tokamak Energy and still under development. The TF coils are cooled to 20K by a cryo-free system. Now claims the world record for the longest duration tokamak plasma at 29 hours, set in July 2015. The discharge was driven by a 600W RF supply but the plasma current has not yet been measured. There is considerable skepticism about this claim - see the records page. Further operation is planned, using a 2.45 GHz heating and current drive system.
ST40	UK Milton Park, Abingdon/td>	2017	1.7 - 2.0	0.40	3	2	?	-	-	-	Merging compression techniques for plasma breakdown, using a minimal central solenoid to maintain the flat top current. Designed for a palsma current up to 2MA and reports in July 2018 suggest that currents approaching 0.4MA have been achieved already. At the same time, plasma temperatures of 15 million degrees are said to have been measured using Dopler spectroscopy.
START	UK Culham	1991-1998	1.25	0.3	0.5	0.31	-	-	1	-	First 'hot' ST, achieved world record betaT =40%. To ENEA at Frascati, June 2004 to become Proto-Sphera.
STPC-EX	Turkey Ankara	1986	1.5	0.084	0.12	0.0065	-	-	-	-
SUNIST Sino UNIted Spherical Tokamak	China Beijing	2003	1.3	0.3	0.15	0.05	0.1	?	?	?	Double null divertor / limiter. 0.2MW of EBW heating. ECRH heating system mainly used for pre-ionisation. Currently installing a 0.5 to 1MHz, 100kW, power supply and antenna for Alfven Wave heating and current drive.
TS-3	Japan Tokyo	1986	1.4	0.2	0.2	0.3	-	-	-	-	Limiter machine
TS-4	Japan Tokyo	2000	1.2	0.55	0.5	0.08	-	-	-	-	Limiter machine
TST-2 Tokyo Spherical Tokamak	Japan Tokyo	1999	1.5	0.38	0.4	0.2	0.2 EBW	-	-	-	Major upgrade of TST-M. Double null divertor / limiter. 0.2 sec pulses. Studying plasma turbulence. Upgrades to heating and current drive systems planned soon.
UTST	Japan Tokyo	2007	1.6	0.39	0.3	0.31	-	-	0.7	-	Ultra-high beta discharges using the double-null merging method. All PF coils outside the vacuum vessel.