Stability Analysis of Two-dimensional Current Sheets at Arbitrary Aspect Ratio
Abstract
Magnetohydrodynamic simulations suggest that there exists a threshold Lundquist number Sc, around Sc 104, above which current sheets transition from a laminar, Sweet-Parker like reconnecting configuration, to a highly tearing-unstable (turbulent) state dominated by plasmoid generation. In this context, it is known that the flow along the sheet plays a stabilizing role, as one would expect the evacuation time-scale to be longer than the typical growth time for islands in order for the sheet to be tearing unstable. However, a satisfactory detailed explanation of the critical threshold for the tearing instability and its dependence on boundary conditions is still lacking. Here we present results from linear stability analysis of two-dimensional current sheets with flows across and along the sheet, spanning a wide range of Lundquist numbers (S) and current sheet aspect ratio. Since the growth rate of the tearing mode is strongly affected by the aspect ratio, we inspect how it should scale with S in order to overcome the stabilizing effect of flows. This work complements a companion one on one-dimensional sheets embedded in a jet, highlighting the effects introduced by both inhomogeneity along the sheet and boundary conditions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMSH51B2596S
- Keywords:
-
- 2164 Solar wind plasma;
- INTERPLANETARY PHYSICSDE: 2169 Solar wind sources;
- INTERPLANETARY PHYSICSDE: 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7524 Magnetic fields;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY