Observation of explosive collisionless reconnection in 3D nonlinear gyrofluid simulations

¹ Max-Planck-Institut für Plasmaphysik, EURATOM Association - D-85748 Garching, Germany, EU
² Max-Planck-Institut für Sonnensystemforschung - D-37191 Katlenburg-Lindau, Germany, EU

Received: 20 October 2011
Accepted: 25 November 2011

Abstract

The nonlinear dynamics of collisionless reconnecting modes is investigated, in the framework of a three-dimensional gyrofluid model. The collisionless regime is the relevant regime of high-temperature plasmas, where reconnection is made possible by electron inertia and has higher growth rates than resistive reconnection. The presence of a strong guide field is assumed, in a background slab model with Dirichlet boundary conditions in the direction of nonuniformity. Values of ion sound gyro-radius and electron collisionless skin depth much smaller than the current layer width are considered. Strong acceleration of growth is found at the onset to nonlinearity, while at all times the energy functional is well conserved. Nonlinear growth rates more than one order of magnitude higher than linear growth rates are observed when entering the small-Δ ′ regime.