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| 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.
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