Mode Coupling in the Solar Corona. IV. Magnetohydrodynamic Waves

Abstract

A general theory for coupling between MHD waves obliquely incident on a stratified medium is developed. Coupling between the Alfvtln mode and the magnetoacoustic mode (the fast mode for VA > c_s and the slow mode for V_A < c_s) is affected little by the finiteness of C_s/V_A for VA >> C_s and the coupling becomes weaker as C_s/V_A is increased towards unity. Coupling between the fast and slow modes for V_A ≈ C. is discussed qualitatively using solutions of the MHD counterpart of the Booker quartic equation.