On the theory of coronal heating mechanismsThe present state-of-the-art of two classes of theories of coronal heating is examined: (1) heating by acoustic processes in the 'nonmagnetic' parts of the atmosphere (the shock-wave theory is an example); and (2) heating by electrodynamic processes in the magnetic regions of the corona (beta much less than 1) either by MHD waves or current heating in regions with high electric current densities (flare-type heating). It is concluded that the mechanism of the heating of the solar chromosphere and corona remains an open question, especially in explaining detailed atmospheric structures. The acoustic theory might be correct with little modification for most of the chromosphere, but as soon as the atmosphere shows a high degree of structure as in the corona and transition layer the magnetic field must play a dominant role. It appears that the current heating theories have a small range of applicability, while the MHD-wave theories are the most promising.
Document ID
19820028017
Acquisition Source
Legacy CDMS
Document Type
Other - Collected Works
Authors
Kuperus, M. (Utrecht Rijksuniversiteit, Utrecht, Netherlands)
Ionson, J. A. (NASA Goddard Space Flight Center Laboratory for Astronomy and Solar Physics, Greenbelt, MD, United States)
Spicer, D. S. (U.S. Navy, E. O. Hulburt Center for Space Research, Washington DC, United States)