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Wave propagation and absorption are investigated in the vicinity of the first ion cyclotron harmonic resonance. Two regimes, dominated by mode conversion to Bernstein waves and by ion cyclotron damping respectively, are identified, depending on the value of k(parallel) and the density and temperature of resonant ions. With the help of analytic solutions of the fourth order finite Larmor radius (FLR) wave equations, simple expressions are derived for the reflection and transmission of a fast wave impinging on the resonance, and for the efficiency of mode conversion through the resonance layer. The solutions of the second order wave equations obtained by order reduction are also investigated. This approximation eliminates the short wavelength Bernstein waves, and replaces mode conversion by an equivalent power sink. The solutions of the order reduced equations can be used to obtain accurate estimates of direct ion cyclotron harmonic damping in the mode conversion regime. Absorption in the cyclotron damping regime can be obtained from the WKB solutions. Simple interpolation formulae covering both regimes are suggested, and compared with numerical results obtained with the FELICE code. The results obtained can be used to evaluate the heating efficiency of a given antenna and for fast modelling of this heating scenario without extensive numerical calculations. Applications to ASDEX Upgrade and ITER are presented.

Additional information

Authors: BRAMBILLA M, Max-Planck-Institut für Plasmaphysik, Garching bei München (DE)
Bibliographic Reference: Report: IPP 5/52 EN (1993) 38 pp.
Availability: Available from Max-Planck-Institut für Plasmaphysik, 8046 Garching bei München (DE)
Record Number: 199311391 / Last updated on: 1994-11-28
Original language: en
Available languages: en