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Probing Surface Flows and Magnetic Activity with Time-Distance Helioseismology

Published online by Cambridge University Press:  13 May 2016

L. Gizon ,
T. L. Duvall Jr.  and
R. M. Larsen
L. Gizon
Affiliation:
HEPL, Stanford University, Stanford CA 94305, USA
T. L. Duvall Jr.
Affiliation:
NASA/Goddard Space Flight Center, Greenbelt MD 20771, USA
R. M. Larsen
Affiliation:
HEPL and SCCM, Stanford University, Stanford CA 94305, USA

Abstract

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We estimate near-surface flows using the techniques of f-mode time-distance helioseismology together with MDI/SOHO data. (1) Synoptic maps of horizontal flows are obtained for 1996, 1998 and 1999. Rotation, torsional oscillations and meridional circulation are measured. We detect weak large-scale flows converging toward active regions. Travel times are found to be shorter at locations of high magnetic activity. In addition, we measure the motion of the supergranulation pattern. (2) Realistic travel-time sensitivity kernels are used in an iterative deconvolution to infer horizontal flows at a high spatial resolution. The radial outflow outside a sunspot penumbra, called the moat, is measured.

Type
Session II: Convection Zone and Local Area Helioseismology
Information
Symposium - International Astronomical Union , Volume 203: Recent Insights into the Physics of the Sun and Heliosphere: Highlights from Soho and Other Space Missions , 2001 , pp. 189 - 191
Copyright
Copyright © Astronomical Society of the Pacific 2001 

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