Oscillatory regimes of compressible 2.5D viscous linear magnetic reconnection

Abstract

We investigate the dynamics and energetics of magnetic reconnection in a general linear magnetohydrodynamic (MHD) model. Our investigation is threefold: First, we formulate a generalized 2.5D linearized MHD system in the presence of viscous, pressure, collisionless, and axial magnetic effects. Second, we find, in accordance with previous studies, that viscous effects, while reducing the rate of reconnection, boost the rate of total energy release. Moreover, viscous dissipation, as opposed to resistive dissipation, is unlikely to be impeded by pressure forces. Third, we compare two different equilibrium axial magnetic field profiles. One profile emulates a quasiseparatrix layer and the other profile emulates a 3D null point. In 2.5D, these profiles actually correspond to a hyperbolic field threaded by an axial field and a null line, respectively. We show evidence that fast reconnection is only attainable in the presence of a null.