Studied is the stopping and transport of relativistic fast electrons in the vicinity of compressed dense plasma core relevant to fast ignition. Electromagnetic cascade Monte-Carlo is coupled to 2D-PIC simulation. The 2D PIC simulates input electron energy spectrum and angular dependence. The electron energy distributions after passing through the plasma core are calculated at different viewing angles, which well agree with the experiment below several MeV energy range. The implications of calculated results as to collisional damping on several MeV electrons are discussed with the theory based on the stopping power model. The spatial distribution of plasma temperature is also estimated via deposited energy by fast electrons, showing the strong heating at the core surface.

Abstract.We have studied energy distribution of fast electrons passing through a highly compressed core plasma for fast ignition research in inertial confinement fusion. Recent PIC calculations indicate that the collective effect of electric and magnetic fields on the transport may be less significant than the binary collisions in the case of a high density fusion pellet. In order to understand the net effect of binary collisions in dense plasma, we calculate electron energy distributions at several viewing angles using an electromagnetic cascade Monte-Carlo simulation, EGS5, for estimation of the contribution of multi collisional process. Here, the construction of physical parameters in the code were taken from the calculation results given by 2 dimensional particle-in-cell simulations.In the result, the number of electrons detected on the laser axis within the range to 15 MeV significantly decreases for the superdense region (max: 1.6 · 10 25 [/cm 3 ]) compared with the low density plasma. The reduction on the electron number decreases with increase of observation angles gradually and finally the number almost coincides more than 40 degrees.