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Thermal and mechanical damping of solar p-modes

Goldreich, Peter and Kumar, Pawan (1991) Thermal and mechanical damping of solar p-modes. Astrophysical Journal, 374 (1). pp. 366-368. ISSN 0004-637X. doi:10.1086/170126.

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Nonadiabatic effects associated with the transfer of energy and with turbulent stresses add small imaginary parts, ω_i^(1) and ω_i^(2), to solar p-mode eigenfrequencies. Numerical calculations have shown that these quite different processes make comparable contributions to ωi at frequencies well below the acoustic cutoff at ω_(ac). We derive analytic expressions which reveal the connection between ω_i^(1) and ω_i^(2). Our estimates yield ω_i ∝ ω^8 for ω « ω_(ac), in good agreement with the numerical calculations. However, the observed line width is proportional to ω^(4.2) at low frequencies. We suspect that there is an unmodeled component of perturbed convective energy transport or of turbulent viscosity that makes an important contribution to ω_i at ω « ω_(ac).

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Additional Information:© 1991 American Astronomical Society. Received 1990 February 26; accepted 1990 December 5. We thank N. Balmforth, J. Christensen-Dalsgaard, and K. Libbrecht for helpful discussions. We are especially indebted to Y. Osaki for critical comments that allowed us to improve upon an earlier version of this manuscript. This research was supported by NSF grant AST 89-13664 and NASA grant NAGW 1303. Part of it was performed while P. G. was visiting the Harvard-Smithsonian Center for Astrophysics, and P. K. was visiting the Institute for Theoretical Physics at Santa Barbara. P. G. is grateful to the Smithsonian Institution of Washington for the award of a Regents Fellowship.
Group:UNSPECIFIED, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
NSFAST 89-13664
Smithsonian Institution of Washington Regents FellowshipUNSPECIFIED
Subject Keywords:radiative transfer, Sun: oscillations, turbulence
Issue or Number:1
Record Number:CaltechAUTHORS:20130313-154444141
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Official Citation:Thermal and mechanical damping of solar p-modes Goldreich, Peter; Kumar, Pawan Astrophysical Journal, Part 1, vol. 374, June 10, 1991, p. 366-368.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37510
Deposited By: Ruth Sustaita
Deposited On:14 Mar 2013 15:22
Last Modified:09 Nov 2021 23:29

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