Effect of variation of magnetic field direction of hydromagnetic surface waves

The dispersion equation for the hydromagnetic surface waves along the interface between two compressible plasma media is discussed for general values of the different parameters arising in the problem when the magnetic fields across the interface vary both in magnitude and direction. The propagation characteristic of both the slow and fast modes show variations with the angle between the magnetic field directions on either side of the interface. Most interesting result being the existence of critical angle between the magnetic field for which the propagation band for surface wave becomes zero and both the modes propagate with constant bulk Alfven velocity in either media, without showing any compressibility effects.