Numerical simulation of collective ion acceleration in the laser controlled collective accelerator

Summary Form only given, as follows. In the Laser Controlled Collective Accelerator, an intense electron beam is injected at a current above the vacuum space-charge limit into an initially evacuated drift tube. A plasma channel, produced by time-sequenced, multiple-laser-beam ionization of a solid target on the drift tube wall, provides the necessary neutralization to allow for effective beam propagation. By controlling the rate of production of the plasma channel as a function of time down the drift tube, control of the electron beamfront can be achieved. Initial experiments have demonstrated the controlled acceleration of protons at a rate of 40 MeV/m over a distance of 50 cm, in good agreement with experimental design values. In order to understand and to optimize ion acceleration in this system, the one-dimensional electrostatic PIC code CIA has been developed. Initial results agree with the experimental results as regards rate of sequencing for enhanced acceleration and peak enhanced ion energy. In addition, the code demonstrates the erosion of the strong beamfront electric field as well as the decrease in the number of ions accelerated over the channel length.<>