Back to Volume
Paper: Excitation, Propagation and Conversion of Helioseismic MHD Waves in Strong Field Regions
Volume: 416, Solar-Stellar Dynamos as Revealed by Helio- and Asteroseismology: GONG 2008/SOHO 21
Page: 61
Authors: Parchevsky, K. V.; Kosovichev, A. G.
Abstract: We present the results of 3D numerical simulations of MHD wave excitation, propagation, and conversion in various configurations of the background magnetic field, including realistic models of sunspots. The background field causes anisotropy of the wave amplitude along the wave front and distortion of the wave front itself. This effect is stronger for f- than for p-modes. Comparison of calculated travel time variations caused by the magnetic field with observations obtained from MDI Doppler velocity data shows that only about 25% of the observed mean travel time variation around sunspots can be explained by the direct interaction of MHD waves with the inclined magnetic field (even for strong fields of 1400-1900 G). We show that for a height of 300 km and such strong fields the phase of the simulated travel time variations coincides with the observed phase.
Back to Volume