Tearing And Surface Preserving Electron Magnetohydrodynamic Modes In A Current Layer

In this paper, we have carried out linear and nonlinear analysis of tearing and surface preserving modes of two-dimensional electron magnetohydrodynamics. A linear analysis shows that the perturbations parallel to equilibrium magnetic field B-0 (characteristic tangent hyperbolic spatial profile), driven by the current-gradients, lead to two different modes. The first mode is the tearing mode having a non-local behavior, which requires the null-line in the magnetic field profile. Whereas, the second mode is a surface preserving local mode, which does not require the null-line in the magnetic field. The quantity B-0 - B-0 '' should change sign for these modes to exist. In nonlinear simulations, for tearing case, we observe the formation of magnetic island at the null-line due to the reconnection of magnetic field lines. However, for surface preserving mode, a channel like structure is observed instead of the island structure. (C) 2016 AIP Publishing LLC.