Study of Pre-Plasma Effects on Fast Electron Generation and Transport Using the 1.5kJ, 10ps OMEGA EP Laser

The efficient coupling of high intensity laser energy to fast electrons and their subsequent transport is of great interest to fast ignition inertial confinement fusion. Recent 10-ps experiments performed on the OMEGA EP laser show significantly different dynamics of fast electrons depending on pre-pulse level [1]. Here we present the detailed analysis of bremsstrahlung data used to understand the fast electron energy deposition in the target. The fast electron transport is modeled with the Monte-Carlo code package ITS 3.0 and with the hybrid-PIC code Zuma, which includes particle induced fields. We show increase in electron temperature and conversion efficiency and decrease in divergence when pre-pulse is reduced. We also show that fields play a role in electron transport with 10-ps pulses.\\[4pt] [1] M.S. Wei, ``Investigation of the Dependence of Fast-Electron Generation and Transport on Laser Pulse-Length and Preplasma,'' SSAP Symposium (2013)