A theory of fast-wave absorption, transmission, and reflection in the ion cyclotron range of frequencies

Abstract

A second-order differential equation for the fast wave propagating in a hot, two-ion species plasma is obtained. This second-order approximation is obtained unambiguously and allows the wave amplitude to be identified with one of the electric field components. The approximation is based on replacing the coupling to the ion-Bernstein wave by a localized perturbation of the fast wave. For the case of perpendicular propagation, the second-order equation reduces to Budden’s equation giving the well-known transmission coefficient for both two-ion hybrid and second-harmonic resonance. The equation includes the effect of simultaneous minority fundamental and majority second-harmonic cyclotron damping. The solutions of the second-order equation as a function of n∥ give absorption transmission and reflection coefficients that agree well with the results based on models giving higher-order differential equations and solved by means of much more complex numerical codes.

Damping of the fast Alfvén wave in ion-cyclotron resonance heating

“…These criteria require a larger kI 1 for decoupling than the k 1 1 required by previous criteria [7].…”

“…These simpler models lend themselves to an easier understanding of this type of heating. The construction of such models requires the reduction in the order of the differential equation description of the mode-conversion process (7,8].…”

Effects of Heavy Ions on ULF Wave Resonances Near the Equatorial Region

“…The mode conversion in warm plasmas indicates that the II resonance typically leads to the electron heating via the excitation of ion Bernstein waves [e.g. , 1976;Brambilla and Ottaviani , 1985;Lashmore-Davies et al, 1988;Majeski et al, 1994;Fuchs et al, 1995]. As discussed in the previous sections 4.1 and 4.2 above, our fluid model is restricted to relatively large scale phenomena (> ρ ci ).…”

“…effects [e.g. Swanson, 1976;Jacquinot et al, 1977;Perkins, 1977;Lapierre, 1983;Brambilla and Ottaviani , 1985;Riyopoulos and Tajima, 1986;Lashmore-Davies et al, 1988;Fuchs et al, 1995]. The mode conversion in warm plasmas indicates that the II resonance typically leads to the electron heating via the excitation of ion Bernstein waves [e.g.…”

Heating and current drive by mode-converted ion-Bernstein waves

“…where y is the normalized (poloidal) component of the electric field, x is the normalized spatial coordinate along the equatorial plane, and Q(x) is the potential function [4], which for a cold plasma is equal to the righthand side of (1).…”