Alfvenic and magnetosonic resonances in a nonisothermal plasma

Abstract

We investigate the problem of the incidence and reflexion of a monochromatic magnetosonic wave at the transition plasma layer with two resonant surfaces—for the Alfven and slow magnetosonic oscillations. A qualitative analysis of the solution to this problem is performed. It is shown that absorption of the incident wave energy at the transition layer increases substantially when there is a resonant surface for slow magnetosonic oscillations. In the neighbourhood of this resonant surface, the energy of an incident wave is totally absorbed, resulting in additional plasma heating. There is a range of frequencies and wavelengths for which the absorption coefficient is 100%. Our numerical calculations have shown that the energy absorption coefficient for an incident fast magnetosonic wave in plasma with β ∼ 1 exceeds its counterpart in ‘cold’ plasma or in a plasma configuration with one resonant surface, for Alfven waves only.