Plasma heating and losses in toroidal multipole fields

Conference · Wed Jan 01 04:00:00 EST 1975

OSTI ID:4184708

Armentrout, C J; Barter, J D; Breun, R A

The heating and loss of plasmas have been studied in three pulsed, toroidal multipole devices: a large levitated octupole, a small supported octupole and a very small supported quadrupole. Plasmas are produced by gun injection and heated by electron and ion cyclotron resonance heating and Ohmic heating. Electron cyclotron heating rates have been measured over a wide range of parameters, and the results are in quantitative agreement with stochastic heating theory. Electron cyclotron resonance heating produces ions with energies larger than predicted by theory. With the addition of a toroidal field, Ohmic heating gives densities as high as 10$sup 13$ cm$sup -3$ in the toroidal quadrupole and 10$sup 12$ cm$sup -3$ in the small octupole. Plasma losses for n = 5 x 10$sup 9$ cm$sup -3$ plasmas are inferred from Langmuir-probe and Fabry- Perot interferometer measurements, and measured with special striped collectors on the wall and rings. The loss to a levitated ring is measured by using a modulated light beam telemeter. The confinement is better than Bohm but considerably worse than classical. Low-frequency convective cells which are fixed in space are observed. These cells around the ring are diminished when a weak toroidal field is added, and loss collectors show a vastly reduced flux to the rings. Analysis of the spatial density profile shows features of B- independent diffusion. The confinement is sensitive to some kinds of d. c. field errors, but surprisingly insensitive to perturbations of the a. c. confining field. (auth)

• Research Organization: Univ. of Wisconsin, Madison
• NSA Number: NSA-33-005151
• OSTI ID: 4184708
• Country of Publication: IAEA
• Language: English

Related Subjects

*PLASMA HEATING-- ICR HEATING
*THERMONUCLEAR DEVICES-- ICR HEATING
700101* --Fusion Energy--Plasma Research--Plasma Confinement & Heating
ENERGY LOSSES
FABRY-PEROT INTERFEROMETER
LANGMUIR PROBE
MULTIPOLAR CONFIGURATIONS
N70100* --Physics--Controlled Thermonuclear Research-- Confinement & Heating
TOROIDAL CONFIGURATION