Numerical Simulations of Oscillations in Solar Corona Excited by Vortex Shedding

Abstract

We study transverse oscillations of plasma structures in the solar corona excited by vortex shedding solving the full set of the 3D ideal time-dependent magnetohydrodynamic equations. To present how the creation of vortices and excited oscillations depend on the initial flow speed and various values of the magnetic field, we performed a parametric study for two cases, an interaction of a steady flow with a rigid and spatially fixed cylindrical obstacle, and with a cylinder fixed at the boundaries. We show that generated vortices can excite oscillations, e.g., transverse (kink), in the solar corona, for example in coronal loops, filaments, flux ropes, or similar magnetic structures. It has been found that the oscillation period is close to the theoretically predicted value. Moreover, we study the dependence of the Strouhal number with respect to the magnetic field under the conditions of the solar atmosphere.