HR: 1330h
AN: SP13A-02    [Abstracts]
TI: The Effects of Inclined Magnetic Field over Time-Distance Measurements
AU: * Zhao, J
EM: junwei@quake.stanford.edu
AF: Hansen Experimental Physics Laboratory, Stanford University, 455 via Palou, Stanford, CA 94305-4085
AU: Kosovichev, A G
EM: sasha@quake.stanford.edu
AF: Hansen Experimental Physics Laboratory, Stanford University, 455 via Palou, Stanford, CA 94305-4085
AB: Recent observation by phase-sensitive acoustic holography has shown that the inclined magnetic field has significant effects over the local helioseismology measurements, and it was thus suggested that the acoustic wave phase shift is substantially caused by the photospheric magnetic field. We make the similar measurements by use of time-distance helioseismology technique over a sunspot when it rotated from the solar east limb to the west. We find that the wave travel time is often longer in the part of sunspot penumbra that is closer to the solar disk center, similar to what was found by acoustic holography analysis. We investigate the other possible reasons that may cause this effect, e.g., projection effect, Doppler velocity masking effect, and find these effects do not account for all the travel time variations. We perform time-distance inversions to investigate how these measurements affect interior structures inferred from inversions.
DE: 7522 Helioseismology
DE: 7524 Magnetic fields
SC: Solar Physics Division - AAS [SP]
MN: 2005 Joint Assembly