A numerical study of electron-magnetohydrodynamics tearing modes in parameter ranges of experimental interest

Abstract

We perform a numerical study of the linear dynamics of tearing modes in slab incompressible electron-magnetohydrodynamics (EMHD) by considering some parameter ranges, which can be of interest for laboratory plasmas (e.g., helicon devices) or for astrophysics (e.g., solar-wind turbulence). To this purpose, several non-ideal effects are simultaneously retained (finite electron inertia, resistivity, and electron viscosity), and we make distinction between the dissipation coefficients in the direction parallel and perpendicular to the guide field. We thus identify some new reconnection regimes, characterized by a departure from the customary monotonic power-law scalings of the growth rates with respect to the non-ideal parameters. The results here presented can provide a useful indication for future studies of EMHD regimes relevant to experiments and for extensions of the EMHD tearing mode modeling to more complete regimes including kinetic effects (e.g., “electron-only” reconnection in kinetic regimes).