Article ID Journal Published Year Pages File Type
1766662 Advances in Space Research 2007 5 Pages PDF
Abstract

A model of time-dependent Petschek-type reconnection of arbitrary strong magnetic fields is presented where all necessary relativistic effects are taken into account. Reconnection is supposed to be initiated due to a local decrease of the plasma conductivity inside the diffusion region, which results in the appearance of an electric field along the X-line. This electric field is considered as a given arbitrary function of time. Then all MHD parameters as well as the shape of the moving Petschek-type shocks are obtained from the ideal relativistic MHD equations written in terms of 4-magnetic field and 4-velocity vectors as suggested by Lichnerowicz. The analysis is restricted to a symmetric current sheet geometry and to the case of weak reconnection, where the reconnection rate is supposed to be a small parameter. The solution obtained extends the well-known Petschek model for the steady-state case to incorporate relativistic effects of impulsive reconnection. It is shown that the plasma is accelerated at the slow shocks to ultrarelativistic velocities with high Lorentz-factors only for current layers embedded into strong magnetic fields and low-beta plasmas. In this case the plasma is strongly compressed and heated while the normal size of the outflow region with the accelerated plasma becomes very small.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Space and Planetary Science
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