Theoretical Estimation and Multiparticle Simulation on Evolution of Longitudinal and Transverse Temperatures During Pulse Compression in Compact Simulator for Heavy Ion Inertial Fusion

Kinetic energy exchange in the longitudinal and transverse directions of a charged particle beam during longitudinal pulse compression is discussed through a compact beam simulator for heavy ion inertial fusion. With the goal of understanding the beam behavior in a compact beam simulator experiment, the evolution of the transverse and longitudinal thermal spreads is evaluated using theoretical estimation and numerical simulation. The multiparticle simulation results show the longitudinal and transverse coupling motions via the space charge effect during the longitudinal pulse compression. The ratio of effective temperatures in the longitudinal and transverse directions derived from numerical results is higher than that evaluated from theoretical estimation. It is implied that the discrepancy is caused by the nonlinear space charge effect during the longitudinal bunch compression.