Filters
Results 1 - 1 of 1
Results 1 - 1 of 1.
Search took: 0.028 seconds
AbstractAbstract
[en] A novel, non-inductive current drive technique has been developed for initiating and maintaining tokamak discharges in CDX-U: the current drive experiment-upgrade, a low-aspect-ratio tokamak facility. The new method utilizes naturally occurring internally generated currents which are present in toroidal plasmas. On CDX-U, electron cyclotron heating (ECH) was used to provide the heating power necessary to create and maintain a high-βpol plasma, the plasma for which self-generated currents are significant. A novel poloidal field configuration provided initial confinement or an ECH produced, trapped electron population. The ECH power, injected through a simple (non-phased) waveguide, was well suited to produce a hot, low-collisionality electrons needed for current generation. With application of ECH, internal plasma generated currents occurred spontaneously and increased with applied ECH power. The generated current scaled inversely with neutral particle density, showing the importance of reducing the plasma collisionality. The current direction depended only on the poloidal field direction. The currents flowing into segmented limiters were very small, confirming that the currents were internally generated. With application of ∼8 kW of ECH power, a toroidal plasma current of up to 1200 A was generated. The poloidal fields from the plasma currents were sufficiently large to form a low-aspect-ratio tokamak plasma. The βpol in this experiment was high. The normalized collisionality was less than one in regions of strong current density. It is possible to generate plasma currents, even when the magnetic topology is changing. In CDX-U, the equilibrium evolved from an open field line configuration to a closed field line tokamak configuration
Primary Subject
Source
1992; 216 p; Princeton Univ; Princeton, NJ (United States); Available from University Microfilms, P.O. Box 1764, Ann Arbor, MI 48106 (United States). Order No. 92-30,224; Thesis (Ph.D.).
Record Type
Miscellaneous
Literature Type
Thesis/Dissertation
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue