Investigation of superthermal asymmetric electron distributions using electron-cyclotron wave transmission in tokamaks
The asymmetric electron distribution generated during lower-hybrid current drive is computed using a 3-D Fokker-Planck code. The superthermal tail and the resulting current are generally a combination of two components with opposite toroidal directions. An appropriate method for experimental investigation of the two superthermal populations is wave transmission of two equivalent rays with equal and opposite values of the parallel refractive index. These equivalent rays can be realised for wave launch from symmetric positions with respect to the equatorial plane at equal and opposite angles in the toroidal direction. Using the appropriate ray-tracing code, the damping of the two rays is computed and is shown to result from electrons with opposite parallel velocities. The differential transmission is then a measure of the overall asymmetry of the electron momentum distribution.
Bibliographic Reference: Report: EUR-CEA-FC-1389(b) EN (1990) 23 pp.
Availability: Available from CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Record Number: 199011262 / Last updated on: 1994-12-01
Original language: en
Available languages: en