Linear waves and reconnecting instabilities in slab magnetised low-beta non-relativistic electron-positron plasmas

The properties of a non-relativistic low-beta magnetised electron-positron plasma in slab geometry are investigated. The two species are taken to be drift-kinetic while we retain Larmor radius effects in quasi-neutrality, and inertia in Ohm’s law. It is shown that the system supports collisionless dispersive waves, which can greatly impact nonlinear magnetic reconnection, but only for large β, the ratio of kinetic and plasma pressure. It is found that the drift wave is not present in such plasma. Tearing modes can be driven unstable by equilibrium current density gradients. When the ordering of the fields’ amplitudes is made consistent with those of Zocco & Schekochihin (2011), an improved set of nonlinear fluid-like equations is derived where magnetic compressibility must be included, and drift waves contributions do not cancel.