Stochastic heating in ultra high intensity laser-plasma interaction: theory and PIC code simulations.

Introduction A large number of issues remain open in the study of laser-matter interaction at very high intensities. Recently, particle-in-cell (PIC) code simulations results published by Tajima et al. have shown that the irradiation of very high intensity lasers on clustered matter leads to a very efficient heating of electrons [1]. They have shown that chaos seems to be the origin of the strong laser coupling with clusters. Therefore, the conditions for the onset of stochastic heating in laser matter interaction have to be explored. In a first part, the theoretical model is presented briefly [2]. PIC code simulations results obtained with the code CALDER [3], for experimentally relevant parameters, are presented in order to confirm the acceleration mecanism predicted by the one-particle theoretical model.