Ion confinement and transport in a toroidal plasma with externally imposed radial electric fields

Technical Report · Thu Mar 01 04:00:00 EST 1979

OSTI ID:5540351

Roth, J R; Krawczonek, W M; Powers, E J; Kim, Y C; Hong, H Y

Strong electric fields were imposed along the minor radius of the toroidal plasma by biasing it with electrodes maintained at kilovolt potentials. Coherent, low-frequency disturbances characteristic of various magnetohydrodynamic instabilities were absent in the high-density, well-confined regime. High, direct-current radial electric fields with magnitudes up to 135 volts per centimeter penetrated inward to at least one-half the plasma radius. When the electric field pointed radially toward, the ion transport was inward against a strong local density gradient; and the plasma density and confinement time were significantly enhanced. The radial transport along the electric field appeared to be consistent with fluctuation-induced transport. With negative electrode polarity the particle confinement was consistent with a balance of two processes: a radial infusion of ions, in those sectors of the plasma not containing electrodes, that resulted from the radially inward fields; and ion losses to the electrodes, each of the which acted as a sink and drew ions out of the plasma. A simple model of particle confinement was proposed in which the particle confinement time is proportional to the plasma volume. The scaling predicted by this model was consistent with experimental measurements.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
• OSTI ID: 5540351
• Report Number(s): N-79-19867
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700105* -- Fusion Energy-- Plasma Research-- Plasma Kinetics-Theoretical-- (-1987)
ANNULAR SPACE
CONFIGURATION
CONFINEMENT
ELECTRIC FIELDS
ELECTRODES
INSTABILITY
PLASMA
PLASMA CONFINEMENT
PLASMA DRIFT
PLASMA INSTABILITY
TOROIDAL CONFIGURATION