Thermal Stability of Static Coronal Loops. I. Effects of Boundary Conditions,
Abstract
We investigate the linear stability of static coronal-loop models undergoing thermal perturbations. The effect of conditions at the loop base on the stability properties of the models is considered in detail. We consider the question of appropriate boundary conditions at the loop base and conclude that the most physical assumptions are that the temperature and density (or pressure) perturbations vanish there. However, if the base is taken to be sufficiently deep in the chromosphere, either several chromospheric scale heights or several coronal loop lengths in depth, then the effect of the boundary conditions on loop stability becomes negligible so that all physically acceptable condition are equally appropriate. For example, one could as well assume that the velocity vanishes at the base. We calculate the growth rates and eigenmodes of static models in which gravity is neglected and in which the coronal heating is a relatively simple function, either constant per-unit mass or per-unit volume. We find that all such models are unstable with a growth rate of the order of the coronal cooling time. The physical implications of these results for the solar corona and transition region are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1985
- Accession Number
- ADA153737
Entities
People
- A. G. Emslie
- C. H. An
- E. C. Shoub
- S. K. Antiochos
Organizations
- Stanford University