WAVE-PROPAGATION IN INHOMOGENEOUS SPACE PLASMAS FROM THE SOLAR ATMOSPHERE VIEWPOINT

The first part of this paper takes the form of a review, concentrating on our Sun's atmosphere as an example of an inhomogeneous space plasma that is observed to support waves. After a description of the atmosphere itself, there is an outline of some solar magnetohydrodynamic (MHD) theory for standing and impulsively generated, propagating waves and a discussion on how the waves are modified by structuring. The time scales that emerge for Alfven and magnetoacoustic waves moving in the solar plasma are identified. As illustrations of attempts to employ the theory, two sets of observations are interpreted in different ways, thus showing how the observed time scales may have alternative but equally plausible explanations. Consideration is then given to how models of wave propagation in the solar atmosphere relate to those of the magnetosphere. Some similarities and differences are discussed and suggestions are made for future wave studies that may be of interest in both solar and magnetospheric physics.