摘要

A reliable analytical expression for the potential of plasma waves with phase velocities near the speed of light is derived. The presented ellipsoid cavity model is more consistent than the previous spherical model and it explains the monoenergetic electron trajectory more accurately especially in the relativistic regime. The electron energy spectrum is also calculated and it is found that the energy distribution ratio of electrons Delta E/E for the ellipsoid model in the here reported condition is about 10%, which is less than half that of the spherical model (25%) and it is in good agreement with the experimentally measured value of 12% under the same condition. The experimental measurements reported here are based on focusing of 500 mJ and 30 fs laser pulse in the best matched point above the pulsed He gas nozzle, which produces a stable ellipsoidal bubble where the obtained electron parameters are much closer to the parameters calculated by the ellipsoidal model. It is found that the quasimonoenergetic electron beam interacting with the laser plasma is more appropriately described with this model.

  • 出版日期2010-3