The Absorption of p-Modes by Sunspots: Variations with Degree and Order
Abstract
A spherical harmonic decomposition of the p-modes into inward and outward propagating waves is employed to investigate the absorption of solar p-modes by an isolated sunspot. The absorption coefficient (averaged over frequency and azimuthal order) is found to increase with increasing horizontal wavenumber k over the range 0-0.8/Mm. For larger horizontal wavenumbers, in the range 0.8-1.5/Mm, the absorption coefficient decreases with increasing k. The absorption along each individual p-mode ridge tends to peak at an intermediate value of the spherical harmonic degree in the range 200-400. The highest absorption is found along the p(1) ridge, and the absorption decreases with increasing radial order.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1993
- DOI:
- 10.1086/172483
- Bibcode:
- 1993ApJ...406..723B
- Keywords:
-
- Absorptivity;
- Solar Oscillations;
- Sunspots;
- Wave Attenuation;
- Acoustic Scattering;
- Helioseismology;
- Power Spectra;
- Solar Physics;
- SUN: OSCILLATIONS;
- SUN: SUNSPOTS