HR: 0800h
AN: SH31A-0220    [Abstracts]
TI: Numerical Simulations of MHD Waves in the Sun
AU: * Parchevsky, K V
EM: kparchevsky@solar.stanford.edu
AF: HEPL, Stanford University, 455 Via Palow, Stanford, CA 94305, United States
AU: Kosovichev, A G
EM: sasha@sun.stanford.edu
AF: HEPL, Stanford University, 455 Via Palow, Stanford, CA 94305, United States
AB: Investigation of propagation, conversion, and scattering of MHD waves in the Sun is very important for understanding the mechanisms of transformation of the acoustic waves into different types of MHD waves. Such studying is also an essential part of developing robust local helioseismology techniques and diagnostics of subsurface magnetic fields. In this studying we investigate excitation, propagation, and conversion of different kinds of MHD waves in presence of the background inclined magnetic field. Waves are generated by the localized force and pressure sources with different frequencies placed at different depths. We have developed a complete linear 3D MHD numerical model to investigate influence of the magnetic field on wave properties and helioseismology measurements in realistic solar conditions. The results show that the magnetic field effects can substantially change the properties of the surface gravity waves (f-mode), but their influence on the acoustic-type waves (p-modes) is rather moderate. We find that magnetic field can lead to a collimation of the wave front. We also observe formation of Alfven waves in our simulations. The numerical modeling and new data from the HMI instrument on SDO will substantially advance our knowledge of the wave interaction with magnetic fields on the Sun and improve the local helioseismology diagnostics.
DE: 7522 Helioseismology
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting