NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Use of acoustic wave travel-time measurements to probe the near-surface layers of the SunThe variation of solar p-mode travel times with cyclic frequency nu is shown to provide information on both the radial variation of the acoustic potential and the depth of the effective source of the oscillations. Observed travel-time data for waves with frequency lower than the acoustic cutoff frequency for the solar atmosphere (approximately equals 5.5 mHz) are inverted to yield the local acoustic cutoff frequency nu(sub c) as a function of depth in the outer convection zone and lower atmosphere of the Sun. The data for waves with nu greater than 5.5 mHz are used to show that the source of the p-mode oscillations lies approximately 100 km beneath the base of the photosphere. This depth is deeper than that determined using a standard mixing-length calculation.
Document ID
19950039787
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Jefferies, S. M. (University of Delaware, Newark, DE United States)
Osaki, Y. (University of Tokyo Tokyo, Japan)
Shibahashi, H. (University of Tokyo Tokyo, Japan)
Duvall, T. L., Jr. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Harvey, J. W. (National Solar Observatory, Tucson, AZ United States)
Pomerantz, M. A. (University of Delaware, Newark, DE United States)
Date Acquired
August 16, 2013
Publication Date
October 20, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 434
Issue: 2
ISSN: 0004-637X
Subject Category
SOLAR PHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF DPP-89-17626
CONTRACT_GRANT: NSF OPP-92-19515
Distribution Limits
Public
Copyright
Other