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Direct Measurement of Wave Kernels in Time-Distance HelioseismologySolar 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)h ave 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-sourc'e 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.
Document ID
20060013114
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Duvall, T. L., Jr.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Geophysics
Meeting Information
Meeting: HMI/AIA Team Meeting
Location: Monterey, CA
Country: United States
Start Date: February 13, 2006
End Date: February 17, 2006
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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