Community Research and Development Information Service - CORDIS

Abstract

The linear propagation of lower-hybrid waves in an axisymmetric plasma (magnetohyrodynamic equilibrium of the Soloviev type) was numerically simulated. The development of k(parallel) (vector component of wave k parallel to the magnetic field B), important for the modelling of the current drive, was studied in terms of the geometric parameters of the equilibrium: the relationship of aspect, ellipticity and triangularity. The results show that k(parallel) depends markedly upon the parameters; the resulting structures are very rich. Two mechanisms were shown to increase k(parallel): - the "resonance" which is produced in the small bands of space of the parameters and is associated with trajectories in (R,Z) close to stabilisation - a stochastic development resembling diffusion in equilibria of very high triangularity. Significant growth of k(parallel) of part of the waves, capable of creating a current within the plasma, was, however, only observed in a minority of cases. Indeed several successful experiments with current drive have been reported whose parameters have been set in such a manner that this model does not forecast the required growth of k(parallel). This model, which is similar to models commonly used, does not therefore explain current drive.

Additional information

Authors: FIVAZ M, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Lausanne (CH);APPERT K, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Lausanne (CH);KRLIN L, Institute of Plasma Physics, Czechoslovak Academy of Sciences, Prague (CS)
Bibliographic Reference: Report: LRP 400/90 FR (1990) 40 pp.
Availability: Available from Confédération Suisse, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, 21 avenue des Bains, 1007 Lausanne (CH)
Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top