On Macro and Micro Structure in Collisionless Reconnection
Abstract
Collisionless magnetic reconnection has been studied by two basically different techniques. 1) Early treatments used MHD equations with a proxy resistivity, intended to simulate dissipation by plasma turbulence or other small scale effects. This simplified, quantitative, analytical, steady state approach led to a weak dependence of reconnection rate on effective resistivity. It was later found, by MHD modeling, that this approach required a resistivity that was zero below a critical current density - matching an instability leading to turbulence. 2) Recent analyses have used more elaborate codes which deal with the particle nature of the plasma using several different assumptions. All of these approaches led to essentially the same reconnection rate and overall configuration. The weak dependence on the specific nature of the dissipation process is due to the weak dependence on effective resistivity found earlier. We will discuss how the macroscopic flow adjusts to the dissipation process to yield the essentially constant reconnection rate. The recent modeling efforts have helped to support the validity of the original MHD results.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 2002
- Bibcode:
- 2002APS..DPPKP1002P