Resonant amplification of MHD waves in realistic subsolar magnetopause configurations

Broadband ULF fluctuations are routinely observed throughout the magnetosheath; the fluctuation level peaks at the magnetopause and becomes very small in the magnetosphere. The present paper analyzes the propagation of magnetosheath waves and the transport of energy at the subsolar magnetopause by means of a linear perturbation analysis in the limit of the MHD approximation. We examine realistic equilibrium magnetopause configurations with a cold and dense magnetosheath and a hot, tenuous magnetosphere, possibly including a trapped magnetopause population. The effects of magnetic field rotation are examined. Resonant amplification of monochromatic magnetosonic waves at the magnetopause is found to occur under various conditions. For a given frequency, several field lines inside the magnetopause layer can resonate simultaneously.