Applications of generalized MHD ray tracing equations

Generalized ray tracing allows for propagation in a slowly-varying medium changing in space and time. This is relevant in media which have velocities comparable with the wave velocity as is the case for solar wind and magnetosheath MHD waves. We show that the cumulative error in the phase is small. Even in a medium changing by 30% per wavelength, the phase error is less than 1/20 radian per wavelength. Thus the method is useful in considering Pc3 interference effects in the magnetosphere. Results of a number of computatuions are presented to illustrate the use of the method.