SIMULATION OF CHARGED-PARTICLE BEAM TRANSPORT IN A GAS-USING A HYBRIDPARTICLE-FLUID PLASMA MODEL

The simulation of charged-particle beam transport in a approximately 1 Torr gas requires accurate plasma-electron modeling. A simple resisti ve model, which assumes local energy deposition and a thermal plasma-e lectron distribution, is indaequate. A hybrid model has been implement ed into the particle-in-cell simulation code, IPROP (The IPROP Three-D imensional Beam Propagation Code, AMRC-R-966, available from D. Welch, Mission Research Corporation, 1720 Randolph Road SE, Albuquerque, NM 87106, September 1987), in which plasma electrons are divided into hig h-energy macroparticle and thermal-fluid components. This model, which includes ''knock-on'' bound-electron collision and runaway sources fo r high-energy electrons, is then used in the simulation of relativisti c electron-beam and ion-beam experiments. Results are found to be in a greement with HERMES III [Performance of the HERMES III Gamma Ray Simu lator, in Digest of Technical Papers, 7th IEEE Pulsed Power Conference , Monterey, CA, 11 June 1989 (Institute of Electrical and Electronic E ngineers, New York, 1989), pp. 26-31] and GAMBLE II [Phys. Rev. Lett. 70, 2573 (1993)] experimental observables.