Modeling Wave Activity in Coronal Active Regions

Wave activity in coronal active regions has been detected recently in EUV and as Doppler velocity oscillations by SOHO, and in EUV by TRACE. The properties of the waves are determined by the excitation mechanism, and by the local physical conditions, such as magnetic field strength and geometry, temperature, and density. It has been demonstrated that the phase speeds of the various wave modes can be determined from observations. Using 3D MHD model I investigate the generation, propagation, and damping of MHD waves in active regions, with the goal of developing a diagnostic tool of active region physical properties. Photospheric magnetograms were used as the boundary conditions for the magnetic field model, and the initial state was constructed using force-free extrapolation, and gravitationally stratified density. Here I expand previous studies, and investigate possible excitation mechanism, as well as the damping of the transverse oscillations due to resistivity, and leakage. I also investigate the generation, propagation, and damping of longitudinal oscillations in the active region loops. In the present study improved boundary and initial conditions are developed, and the effects of chromospheric coupling on the excitation and damping of the waves are investigated.