Particle Acceleration and Magnetic Dissipation in Relativistic Current Sheet of Pair Plasmas

Abstract

We study linear and nonlinear development of relativistic and\nultrarelativistic current sheets of pair plasmas with antiparallel magnetic\nfields. Two types of two-dimensional problems are investigated by\nparticle-in-cell simulations. First, we present the development of relativistic\nmagnetic reconnection, whose outflow speed is an order of the light speed c. It\nis demonstrated that particles are strongly accelerated in and around the\nreconnection region, and that most of magnetic energy is converted into\n"nonthermal" part of plasma kinetic energy. Second, we present another\ntwo-dimensional problem of a current sheet in a cross-field plane. In this\ncase, the relativistic drift kink instability (RDKI) occurs. Particle\nacceleration also takes place, but the RDKI fast dissipates the magnetic energy\ninto plasma heat. We discuss the mechanism of particle acceleration and the\ntheory of the RDKI in detail. It is important that properties of these two\nprocesses are similar in the relativistic regime of T > mc^2, as long as we\nconsider the kinetics. Comparison of the two processes indicates that magnetic\ndissipation by the RDKI is more favorable process in the relativistic current\nsheet. Therefore the striped pulsar wind scenario should be reconsidered by the\nRDKI.\n