Acoustic waves in the solar atmosphere. II. Radiative damping.
Abstract
A method is described for calculating radiative damping of largeamplitude acoustic waves propagating in the solar photosphere and low chromosphere. The basic radiation expressions to be used with the timedependent hydrodynamic equations are derived, the equation of radiative transfer is solved numerically for an atmosphere in which shock discontinuities may arise, and approximations valid in different limiting cases are considered. The numerical solution is tested against an exact solution, and the transfer equation is combined with the hydrodynamic equations to construct a model atmosphere in radiative equilibrium. The methods developed are then employed to determine theoretically the location of the temperature minimum and to investigate the validity of the shortperiod acousticheating theory for the solar atmosphere. A perturbation approach is adopted to compute radiative damping of the acoustic waves, and the time behavior of acoustic waves with various periods is evaluated. The results are taken as convincing evidence that shortperiod acoustic waves constitute the main chromospheric heating mechanism.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 May 1977
 Bibcode:
 1977A&A....57..193K
 Keywords:

 Acoustic Propagation;
 Radiative Transfer;
 Solar Atmosphere;
 Sound Waves;
 Atmospheric Heating;
 Damping;
 Entropy;
 Hydrodynamic Equations;
 Shock Discontinuity;
 Solar Physics