Collisionless Tearing Instability of a Bi-Maxwellian Neutral Sheet with Exact Particle Orbits

摘要

The tearing instability of a neutral sheet may be important to reconnection in the magnetosphere and elsewhere. The use of a bi-Maxwellian Harris equilibrium is broadly applicable to the physical environment and allows a continuous variation from isotropic situations. The integro-differential equation describing the linear tearing instability in the bi-Maxwellian neutral sheet is solved without approximating the particle orbits. Results of this calculation are presented. Comparison between the exact solution and the 3-region approximation motivates the piecewise-straight-line approximation, a simplification which allows faster solution of the integro-differential equation, yet retains the important features of the exact solution. Keywords: Collisionless tearing mode; Anisotropic temperature; Reconnection; Integrodifferential equation. (jhd)