Behaviour of suprathermal electrons accelerated by the lower hybrid wave in the presence of giant sawteeth
The dynamics and localization of fast electrons accelerated by the lower hybrid wave in the presence of giant sawteeth are for the first time investigated by measuring the non-thermal bremstrahlung emission using a hard x-ray tomographic system recently installed in the TORE SUPRA tokamak. This study is carried out in high-density helium plasmas, strongly heated by several MW of ion cyclotron radio-frequency power, in the hydrogen minority scheme, together with 2-3 MW of LH power. While sawtooth activity is clearly observed on thermal bulk contribution, no modulation is detected on the intensity of radiation's emitted by the suprathermal population. This original effect is investigated in details experimentally, and also in the light of simulations of the lower hybrid wave propagation and absorption by using a ray-tracing code coupled with a two-dimensional relativistic Fokker-Planck solver.
Bibliographic Reference: Article: CEA-FC-1673 (1999)
Record Number: 199911531 / Last updated on: 1999-10-29
Original language: en
Available languages: en