ION CYCLOTRON RESONANCE HEATING BY MEANS OF THE FAST WAVE IN A LONGITUDINALLY INHOMOGENEOUS MAGNETIC FIELD
We consider the coupling between the fast wave and the slow ion cyclotron wave in a plasma in which the equilibrium magnetic field is longitudinally inhomogeneous, using a model studied by White, Yoshikawa and Oberman. Such a coupling can only occur when a second ion species is present and for finite k-4F. This configuration is of relevance to mirrors and also tokamaks. An approximate dispersion relation is obtained from the usual cold plasma model by replacing all slowly varying quantities by their value at the coupling point. The resulting equation preserves the cutoff properties of the original equation. The approximate dispersion relation is then used to analyse the mode conversation of the fast wave to the slow wave at the minority resonance. For N-perpendicular identical to c-Ak-1/omega << 1 the transmission coefficient is close to unity but for N-perpendicular <= 1 the transmission becomes very weak and for incidence from the stronger field region the absorption becomes strong. When the wave is incident from the weaker field region the maximum absorption as a function of the minority fraction and N-perpendicular is 25%. Our results are obtained using second order coupling theories, the advantages of which clearly emerge from this example.
Bibliographic Reference: WRITE TO THE LIBRARIAN, UKAEA, CULHAM LABORATORY, ABINGDON, OXON OX14 3DB (UK), MENTIONING REPORT CLM-P 738, 1985
Record Number: 1989123095300 / Last updated on: 1987-01-01
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