EVALUATION OF THE LOCAL HEAT CONDUCTIVITY COEFFICIENT BY POWER MODULATED ELECTRON CYCLOTRON HEATING IN THE WENDELSTEIN VII-A STELLARATOR
An upper bound for the local electron heat coefficient ALEPH(r) in electron cyclotron heated (ECH) discharges is determined experimentally. The method applied uses power modulation of the ECH and measures the time delay of the electron temperature response as a function of radius by means of a multichannel radiometer for second harmonic electron cyclotron emission (ECE). The evaluation is restricted to plasma radii between 3 and 6.5 cm, where the preconditions of the method are best verified experimentally. The theoretical transport model considers only processes related to the electron temperature gradient and neglects the dependence of ALEPH(r) on T-e.
Bibliographic Reference: NUCLEAR FUSION, VOL. 26 (1986), NO. 5, PP. 678-684
Record Number: 1989124133100 / Last updated on: 1987-01-01
Available languages: en