Acoustic wave propagation in the solar atmosphere. I. Linear response to adiabatic wave excitation.
Abstract
We study the response of various solar atmosphere models to excitation by adiabatic small amplitude acoustic waves. Both monochromatic waves and acoustic spectra are considered. We find that upon excitation, strong resonance oscillations of a single frequency develop which are superposed over the excitation signal. These resonances decay exponentially with time; the decay rate varies strongly with the temperature gradient of the model. In realistic and positive gradient atmospheres the decay rate is much faster than in isothermal models, while in negative gradient models it is even slower. Independent of whether the atmosphere is excited by a pulse or by continuous wave action a similar decay behaviour is found. The response to a stochastic wave spectrum is a series of uncorrelated transient events, each with the associated exponential decay of the resonance.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1995
- Bibcode:
- 1995A&A...294..232S
- Keywords:
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- HYDRODYNAMICS;
- WAVES;
- SUN: CHROMOSPHERE;
- SUN: OSCILLATIONS