Fast collisionless magnetic reconnection: Fluid regime and kinetic effects

Collisionless magnetic ¢eld line reconnection exhibits important similarities
under widely di¡erent physical conditions, ranging from the magnetohydrodynamic
regime, of interest for space and high temperature
magnetically con¢ned plasmas, to the electron-magnetohydrodynamic
regime, of interest for the interaction of ultraintense, ultrashort laser pulses
with a plasma. Analytical and numerical results are presented that illustrate
the nonlinear evolution of the reconnection instability in a two dimensional
con¢guration with a neutral line in fluid and in kinetic plasma regimes.
The importance of plasma anisotropy is stressed for the case of laser plasma
interaction.