Damping of Slow MHD Coronal Loop Oscillations by Shocks

Abstract

The damping of slow magnetoacoustic coronal loop oscillations by shock dissipation is investigated. Observations of large-amplitude slow-mode observations made by SUMER show a clear dependency of the damping rate on the oscillation amplitude. Fully nonlinear MHD simulations of slow-mode oscillations in the presence of thermal conduction are performed that show that shock dissipation is an important damping mechanism at large amplitudes, enhancing the damping rate by up to 50% above the rate given by thermal conduction alone. A comparison between the numerical simulations and the SUMER observations shows that although the shock dissipation model can indeed produce an enhanced damping rate that is a function of the oscillation amplitude, the dependency that we found is not as strong as that for the observations, even after observational corrections and the inclusion of enhanced linear dissipation were considered.