Mode conversion of laser radiation in the presence of a magnetic wiggler

摘要

Laser radiation E ~ yA (z) e~iui propagating through a non-uniform plasma along the direction of the density gradient suffers total reflection at the critical layer. However, when a wiggler magnetic field B_2 = XB_2e~(ikwz) exists near the critical layer, the laser drives a Langmuir wave. For suitable values of Bw and km the power transfer from the laser to the Langmuir wave could be as high as 60%, The Langmuir wave deposits its energy on the electrons via Landau damping. This may be an efficient mechanism of laser absorption when large self-generated magnetic fields exist in the plasma.