Filamentation and Energetic Electron Generation in a Plasma Produced from a High Density Gas Jet Irradiated by a TW Laser Pulse

Abstract

Emission of a well-collimated energetic electron beam has been observed from a plasma of which electron density is higher than 10²⁰ cm^-3 produced by a TW Ti:sapphire laser pulse. The maximum energy of the electrons was 2 MeV, and the beam divergence of the MeV electrons was 6-8°. The generation of the MeV electron beam was always accompanied by the appearance of the transition to the disturbed structure from the narrow and smooth channel in the plasma. This result suggests that the generation of the energetic electron beam may be due to a stochastic acceleration in the disturbed plasma. Discussion based on the stochastic acceleration model taking the phase disturbance of a laser field into account is also presented.