The onset of eruptive processes in plasmas. I

Abstract

Bifurcation theory techniques are employed to compare two apparently similar models for the quasistatic evolution of isothermal current sheet equilibria in cosmic plasma structures. The limitations of the approximation of quasistatic evolution are discussed. In spite of the apparent similarity of the models the qualitative bifurcation behavior is entirely different. It is shown that one model necessarily gives a transition from quasistatic to dynamical evolution of the system, while the other is more likely to describe a slow structural transition to a neighboring stable equilibrium branch. The notion of stability employed here is based on the concept of available free energy. The results shed light on the generic properties of such models.