Collisionless tearing instability in a relativistic pair plasma with a power-law distribution function

We study the tearing instability of a current sheet in a relativistic pair plasma with a power-law distribution function. We first estimate the growth rate analytically and then confirm the analytical results by solving numerically the dispersion equation, taking into account all exact particle trajectories within the reconnecting layer. We found that the instability is suppressed when the particle spectrum becomes harder.