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[56.06] Subsurface Observations of Sunspots and Solar Supergranulation

T.L. Duvall Jr. (Laboratory for Astronomy and Solar Physics, NASA/GSFC), A.G. Kosovichev, P.H. Scherrer (Hansen Experimental Physics Lab., Stanford Univ.)

3-d acoustic tomography of the region below the photosphere is providing new insights into sunspots and the apparently convective flow observed at the surface called supergranulation. The tomography is based on the measurement of travel times between different surface locations and is sensitive to subsurface flows and to wave-speed inhomogeneities caused by temperature and magnetic field variations. This study uses dopplergrams from the MDI instrument on the SOHO spacecraft. A flow cell has been seen below sunspots similar to the model of Parker (Ap.J. 230,905-913,1979) in which there is a horizontal inflow near the top of the convection zone, a downflow directly below the sunspot and a horizontal outflow below. The depth of the supergranulation flow will be discussed.

This research is supported by NASA contract NAG5-3077 at Stanford University.

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