HR: 14:00h
AN: SP23C-02    [Abstracts]
TI: Direct Measurement of Wave Kernels in Time-Distance Helioseismology
AU: * Duvall, T L
EM: tduvall@solar.stanford.edu
AF: NASA/GSFC, Laboratory for Astronomy and Solar Physics, Greenbelt, MD 20771 United States
AU: Birch, A C
EM: aaronb@cora.nwra.com
AF: CoRA/NWRA, 3380 Mitchell Lane, Boulder, CO 80301-5410 United States
AU: Gizon, L
EM: lgizon@solar.stanford.edu
AF: Stanford University, Hansen Experimental Physics Laboratory, Stanford, CA 94305-4085 United States
AB: Solar f-mode waves are surface-gravity waves which propagate horizontally in a thin layer near the photosphere with a dispersion relation approximately that of deep water waves. At the power maximum near 3 mHz, the wavelength of 5 Mm is large enough for various wave scattering properties to be observable. Gizon and Birch (2002,ApJ,571,966) have calculated kernels, in the Born approximation, for the sensitivity of wave travel times to local changes in damping rate and source strength. In this work, using isolated small magnetic features as approximate point source scatterers, such a kernel has been measured. The observed kernel contains similar features to a theoretical damping kernel but not for a source kernel. A full understanding of the effect of small magnetic features on the waves will require more detailed modeling.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7522 Helioseismology
DE: 7524 Magnetic fields
DE: 7529 Photosphere
SC: Solar Physics Division - AAS [SP]
MN: 2005 Joint Assembly