The Equilibrium and Stability of Solar Coronal Magnetic Fields.
Abstract
Available from UMI in association with The British Library. The research of this thesis consists of two main areas of investigation. First, a search for solutions to the equations of magnetohydrostatics was made in an attempt to construct mathematical models of the quasistatic plasma structures embedded in a magnetic field in the solar corona. Several solutions were discovered and their behaviour studied as physical parameters were varied. For example, certain nonlinear solutions were found to exhibit the property that the equilibria could not exist if some mechanism were to increase the plasma pressure beyond some critical value. This kind of scenario has been associated with the explosive dynamic event of the solar flare. When the equilibrium is no longer tenable, it has been suggested that the stored magnetic energy is released in this violent manner. Secondly, the magnetohydrodynamic stability of two of the equilibria have been studied in detail. This provides another possible mechanism for flare development. The equilibrium is subjected to a perturbation of the physical variables and the change in potential energy calculated. If a perturbation can be found for which the potential energy difference is negative, then the underlying equilibrium is linearly unstable. This means that it will try to attain a lower energy state by the release of energy (mainly magnetic). Specific physical criteria for the equilibria to remain stable have been found. In all cases the forcebalance equation has taken account of pressure magnetic and gravitational forces. In particular, the effect of the gravitational force on magnetohydrodynamic stability has been investigated.
 Publication:

Ph.D. Thesis
 Pub Date:
 1988
 Bibcode:
 1988PhDT.........9M
 Keywords:

 Physics: Astronomy and Astrophysics;
 Magnetic Energy Storage;
 Magnetic Fields;
 Magnetohydrodynamic Stability;
 Magnetohydrodynamics;
 Mathematical Models;
 Solar Corona;
 Gravitational Effects;
 Perturbation;
 Plasma Pressure;
 Potential Energy;
 Solar Flares;
 Solar Physics