Radial distribution of superthermal electrons measured with ECE (abstract)

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1146238· OSTI ID:6711776

Preische, S; Kaye, S M; Efthimion, P C; Kaita, R ^[1]

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1. Princeton University, Princeton, New Jersey 08543-0451 (United States)

To aid in the study of lower hybrid current drive as a means of current profile control, the radial profile and velocity distribution of the fast current-carrying electrons and their time evolution must be known. As part of the recent effort to understand this fast electron transport, a diagnostic has been installed on PBX-M to measure the electron cyclotron emission from the fast electrons. An oblique horizontal view of upshifted cyclotron emission in the midplane can give radial as well as velocity space information about the fast electrons. Emission in X mode frequencies refracted by the right-hand cutoff is radially localized. The observed emission at a specific frequency comes only from the radial region [ital r][sub turn][lt][ital r][lt][ital r]([ital B][sub min]), where [ital r][sub turn] is the turning point of the ray, and [ital r]([ital B][sub min]) is given by the condition of the resonance frequency [ital n][sup 2][sub [parallel]]+([ital n][Omega]/[omega])[sup 2][minus]1[ge]0. Emission measured by this new diagnostic has been found to be radially localized as predicted. It is also expected that localized moments of the distribution function may be obtained from these data. A superheterodyne receiver at 60--90 GHz has been built which views the plasma through a focusing gaussian lens antenna at a 57[degree] angle to the toroidal magnetic field. Viewing dumps made of SiC on both the inside and outside walls ensure single pass emission. Results from this new diagnostic will be presented.

• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6711776
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 66:1; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320* -- Plasma Diagnostic Techniques & Instrumentation-- (1992-)
BREMSSTRAHLUNG
CLOSED PLASMA DEVICES
CYCLOTRON RADIATION
DISTRIBUTION FUNCTIONS
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
ELECTRONIC EQUIPMENT
EQUIPMENT
FUNCTIONS
HETERODYNE RECEIVERS
MICROWAVE EQUIPMENT
PBX DEVICES
PLASMA DIAGNOSTICS
RADIATIONS
RADIO EQUIPMENT
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
VELOCITY