Investigation of the formation of a fully pressure-driven tokamak

Journal Article · Sun May 01 00:00:00 EDT 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870708· OSTI ID:6685456

Forest, C B; Hwang, Y S; Ono, M; Greene, G; Jones, T; Choe, W ^[1]; Schaffer, M; Hyatt, A; Osborne, T; Pinsker, R I; Petty, C C; Lohr, J; Lippmann, S ^[2]

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1. Princeton University, Princeton, New Jersey 08543 (United States)
2. General Atomics, San Diego, California 92121-1194 (United States)

A noninductive current drive concept, based on internal pressure-driven currents in a low-aspect-ratio toroidal geometry, has been demonstrated on the Current Drive Experiment Upgrade (CDX-U) [Forest [ital et] [ital al]., Phys. Rev. Lett. [bold 68], 3559 (1992)] and further tested on DIII-D [in [ital Plasma] [ital Physics] [ital and] [ital Controlled] [ital Nuclear] [ital Fusion] [ital Research], 1986, Proceedings of the 11th International Conference, Kyoto (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159]. For both experiments, electron cyclotron power provided the necessary heating to breakdown and maintain a plasma with high-[beta][sub [ital p]] and low collisionality ([epsilon][beta][sub [ital p]][similar to]1, [nu]*[le]1). A poloidal vacuum field similar to a simple magnetic mirror is superimposed on a much stronger toroidal field to provide the initial confinement for a hot, trapped electron species. With application of electron cyclotron heating (ECH), toroidal currents spontaneously flow within the plasma and increase with applied ECH power. The direction of the generated current is independent of the toroidal field direction and depends only on the direction of the poloidal field, scaling inversely with magnitude of the later. On both CDX-U and DIII-D, these currents were large enough that stationary closed flux surfaces were observed to form with no additional Ohmic heating. The existence of such equilibria provides further evidence for the existence of some type of bootstrap current. Equilibrium reconstructions show the resulting plasma exhibits properties similar to more conventional tokamaks, including a peaked current density profile which implies some form of current on axis or nonclassical current transport.

• OSTI ID: 6685456
• Journal Information: Physics of Plasmas; (United States), Vol. 1:5; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
TOKAMAK DEVICES
CURRENT-DRIVE HEATING
COLLISIONLESS PLASMA
ECR HEATING
HIGH-BETA PLASMA
MAGNETIC MIRRORS
PLASMA HEATING
THERMONUCLEAR DEVICES
CLOSED PLASMA DEVICES
ELECTRIC HEATING
HEATING
HIGH-FREQUENCY HEATING
JOULE HEATING
OPEN PLASMA DEVICES
PLASMA
RESISTANCE HEATING
700350* - Plasma Production
Heating
Current Drive
& Interactions- (1992-)