Experimental study of high beta toroidal plasmas

Technical Report · Thu Sep 01 04:00:00 EDT 1983

OSTI ID:5526033

Kellman, A G

Experiments on the Wisconsin Levitated Toroidal Octupole have produced a wide range of stable high ..beta.. plasmas with ..beta.. significantly above single fluid MHD theory predictions. A stable ..beta.. approx. 8% plasma, twice the fluid limit, is obtained with 5 rho/sub i/ approx. L/sub n/ and tau/sub ..beta../ approx. = 6000 tau/sub Alfven/ = 600 ..mu..sec. The enhanced stability is explained with a kinetic treatment that includes the effect of finite ion gyroradius which couples the ballooning mode to an ion drift wave. In a more collisional, large gyroradius (2 rho/sub i/ approx. L/sub n/) regime, a stable ..beta.. approx. 35% plasma is obtained with a decay time of 1000 Alfven times. Measurement of the equilibrium magnetic field in this regime indicates that the diamagnetic current density is five times smaller than predicted by ideal MHD, probably due to ion gyroviscosity. Particle transport is anomalous and ranges from agreement with the classical diffusion rate at the highest beta, lowest field plasma (B/sub P/ = 200 G), to thirteen times the classical rate in a ..beta..=11%, high field plasma (B/sub P/ = 860 G) where the level of enhancement increase with magnetic field. Fluctuations in density, electrostatic potential, and magnetic field have been studied in plasmas with ..beta.. from 0.1% to 40%.

• Research Organization: Wisconsin Univ., Madison (USA). Dept. of Physics
• DOE Contract Number: AC02-76ET53051
• OSTI ID: 5526033
• Report Number(s): DOE/ET/53051-60; ON: DE84004869
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700104* -- Fusion Energy-- Plasma Research-- Plasma Kinetics-Experimental-- (-1987)
ANNULAR SPACE
BALLOONING INSTABILITY
CHARGED-PARTICLE TRANSPORT
CLOSED CONFIGURATIONS
CONFIGURATION
HIGH-BETA PLASMA
INSTABILITY
LEVITATION
MAGNETIC FIELD CONFIGURATIONS
MULTIPOLAR CONFIGURATIONS
OCTUPOLAR CONFIGURATIONS
PLASMA
PLASMA DENSITY
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
RADIATION TRANSPORT
SPACE
TOROIDAL CONFIGURATION