Plasma Current Start-up by Outboard PF Coils in JT-60U and TST-2

Journal Article · Mon Sep 26 00:00:00 EDT 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2098259· OSTI ID:20726346

Takase, Y; Ejiri, A; Ushigome, M ^[1]; Hanada, K ^[2]; Ide, S ^[3]; Mitarai, O ^[4]; Shiraiwa, S ^[5]

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1. University of Tokyo, Kashiwa 277-8561 (Japan)
2. Kyushu University, Kasuga 816-8580 (Japan)
3. Japan Atomic Energy Research Institute, Naka 311-0193 (Japan)
4. Kyushu Tokai University, Kumamoto 862-8652 (Japan)
5. 1-36-2-308 Hakusan, Tokyo 113-00101 (Japan)

Plasma current (Ip) initiation and ramp-up utilizing induction by poloidal field (PF) coils located on the outboard side of the torus were demonstrated in both conventional aspect ratio tokamak (100 kA in JT-60U) and spherical tokamak (10 kA in TST-2). In the presence of sufficient source of plasma by RF ionization (1 MW in JT-60U, 100 kW in TST-2), Ip formation is possible without the existence of a PF null, with the initial vertical field (Bv) in the direction opposite to that required for equilibrium. Utilization of the extra flux swing provided by the PF coils before Bv switches sign is important in arriving at a high enough Ip that matches Bv at the end of PF coil current ramp. In JT-60U, recharging of the OH coil was observed with only perpendicular and counter NB injection, suggesting overdrive by bootstrap current. In TST-2, a quasi-steady-state Ip of 4 kA was formed and sustained by RF power (PRF) alone, without the use of induction. The plasma current centroid of this type of plasma is located on the outboard side. The dependences of Ip on PRF and Bv were found to be weak. The results presented here offer encouragement to CS-less operation of a tokamak fusion reactor, which should have a large impact on the economic competitiveness.

• OSTI ID: 20726346
• Journal Information: AIP Conference Proceedings, Vol. 787, Issue 1; Conference: 16. topical conference on radio frequency power in plasmas, Park City, UT (United States), 11-13 Apr 2005; Other Information: DOI: 10.1063/1.2098259; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ASPECT RATIO
BOOTSTRAP CURRENT
EQUILIBRIUM
HIGH-FREQUENCY HEATING
IONIZATION
JT-60U TOKAMAK
OPERATION
PLASMA
PLASMA PRODUCTION
RF SYSTEMS
SPHERICAL CONFIGURATION
START-UP
STEADY-STATE CONDITIONS
SWITCHES
THERMONUCLEAR REACTORS