High energy electrons accelerated in the field of tightly focused relativistic laser pulse for peak intensity evaluation

Abstract

The action of relativistic femtosecond laser pulse with peak intensity over 1019 W/cm2 onto low density plasma is studied experimentally and numerically. It is demonstrated that electrons may be accelerated up to the relativistic energy (>500 keV) directly by the strong field of tightly focused laser radiation. In dependence on the peak laser intensity a dominant angle of high energy electrons is observed, which is around 45 degree for experimental intensity. On the basis of particles energy and angular distribution the laser pulse peak intensity may be evaluated.