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The tokamak is currently the best toroidal magnetic configuration for confining a plasma in conditions required for thermonuclear fusion. To improve its performance, part of the current needs to be sustained non-inductively, so as to extend the duration of discharges and control the radial profile of current density. A system comprising two antennae was fitted to the tokamak. Experimental injection of hybrid waves showed that a portion of the distribution function of suprathermal electrons is of low velocity parallel to the magnetic field. These electrons can therefore be trapped in local modulations of the toroidal magnetic field. A kinetic model was developed, with which to estimate the loss of electrons due to trapping. This model is based on the quasi-linear interaction of the hybrid wave with the electron population. It can be used to determine the electron distribution function by choosing an absorption profile of the wave in the gas space. Once this distribution is known, the flux of locally deconfined electrons and the power associated with this can be explained in terms of the local plasma conditions. The initial results of this simulation show correlation with the experimental data of a diagnostic measuring the flux of deconfined electrons, given reasonably large radial deposit profiles of the wave in the plasma.

Additional information

Authors: CARRASCO J ET AL., CEA, Département de Recherches sur la Fusion Contrôlée, CEN Cadarache, Saint-Paul-lez-Durance (FR)
Bibliographic Reference: Paper presented: Troisième Congrès de la Société Française de Physique - Plasma, Nancy (FR), September 16-18, 1992
Availability: Available from (1) as Paper EN 37075 ORA
Record Number: 199211486 / Last updated on: 1994-11-29
Original language: fr
Available languages: fr