Compressibility effects on hydromagnetic surface waves

Abstract

The dispersion equation for hydromagnetic surface waves along a plasma-plasma interface has been solved as a function of the compressibility factor c1/vA1, where c1 and vA1 are the acoustic and Alfven wave speed in one of the medium, for general wave propagation direction. Both slow and fast magnetosonic surface waves can exist. The nature and existence of these waves depends on the values of c1/vA1 and θ, the angle of wave propagation. For low-β plasmas only fast mode exists. The slow mode does not propagate below a critical value of c1. When c1 → ∞ the phase velocity of the slow wave tend to the Alfven surface wave velocity in the incompressible media and for large θ the phase velocity of the fast wave approaches this value. The phase velocity of the slow wave increases whereas for the fast wave it decreases with increase in the angle θ.