Explosive reconnection of double tearing modes in relativistic plasmas: application to the Crab flares

TL;DR

This study uses resistive relativistic MHD simulations to explore explosive magnetic reconnection in double tearing modes, potentially explaining the rapid gamma-ray flares observed in the Crab nebula.

Contribution

It demonstrates that secondary instabilities can trigger fast reconnection in relativistic plasmas, with weak dependence on resistivity and magnetization, providing insights into high-energy astrophysical phenomena.

Findings

Secondary instability triggers fast reconnection in DTM.

Reconnection time scale weakly depends on resistivity and magnetization.

Constraints on Lorentz factor and emission region from reconnection dynamics.

Abstract

Magnetic reconnection associated to the double tearing mode (DTM) is investigated by means of resistive relativistic magnetohydrodynamic (RRMHD) simulations. A linearly unstable double current sheet system in two dimensional cartesian geometry is considered. For initial perturbations of large enough longitudinal wavelengths, a fast reconnection event is triggered by a secondary instability that is structurally driven by the nonlinear evolution of the magnetic islands. The latter reconnection phase and time scale appear to weakly depend on the plasma resistivity and magnetization parameter. We discuss the possible role of such explosive reconnection dynamics to explain the MeV flares observed in the Crab pulsar nebula. Indeed the time scale and the critical minimum wavelength give constraints on the Lorentz factor of the striped wind and on the location of the emission region respectively.