Investigations of MHD wave coupling in a 3-D numerical model: effects of temperature gradients Original Research Article

The inhomogeneity of the plasma pressure becomes important near the boundary between cold and hot plasmas. The Alfven speed undergoes significant variations in such regions in order to satisfy the total pressure balance. We have developed a new three-dimensional (3-D) MHD wave model that allows for finite plasma pressure. Based on this time-dependent model, we study the resonant absorption properties when temperature gradients are significant. We consider two models, one corresponding to the inner edge of the plasma sheet while the second models the plasma sheet boundary layer. We discuss how both transverse and compressional waves are affected by inhomogeneous pressure and temperature by examining the wave spectra. Our results show that localized field-aligned currents are strongly excited at the boundary between the plasma sheet and its surrounding regions.