Thermal and Mechanical Damping of Solar p-Modes
Abstract
Nonadiabatic effects associated with the transfer of energy and with turbulent stresses add small imaginary parts, omega-i(1) and omega-i(2), to solar p-mode eigenfrequencies. Numerical calculations have shown that these quite different processes make comparable contributions to omega-i at frequencies well below the acoustic cutoff at omega-ac. Analytic expressions are derived which reveal the connection between omega-i(1) and omega-i(2). The estimates yield omega-i proportional to omega exp 8 for omega much less than omega-ac in good agreement with the numerical calculations. However, the observed line width is proportional to omega exp 4.2 at low frequencies. It is suspected that there is an unmodeled component of perturbed convective energy transport or of turbulent viscosity that makes an important contribution to omega-i at omega much less than omega-ac.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1991
- DOI:
- 10.1086/170126
- Bibcode:
- 1991ApJ...374..366G
- Keywords:
-
- Damping;
- Radiative Transfer;
- Solar Oscillations;
- Photosphere;
- Sound Waves;
- Spectral Line Width;
- Solar Physics;
- RADIATIVE TRANSFER;
- SUN: OSCILLATIONS;
- TURBULENCE