Studied of injected particle trajectories in the beat wave accelerator

The trajectories of relativistic electrons ( gamma =4), injected into the potentials of three-dimensional relativistic plasma waves ( gamma /sub ph/=13.5), have been calculated using Monte Carlo simulation techniques in order to predict quantitatively the output of laser plasma beatwave acceleration experiments. The calculations have permitted the analysis of accelerated (and decelerated) electrons according to the quantity of electrons accelerated, the angular distribution, and the energy spectrum. The calculations have also guided the modification of the electron detection system in order to optimize electron transport and maximize detection efficiency. The radial fields (focusing and defocusing) and longitudinal fields (accelerating and decelerating) that result in the number of electrons accelerated being several orders of magnitude lower than the number injected have been analyzed. The angular distribution of accelerated electrons as a function of final electron energy has been predicted, as well as the final energy spectrum and how it depends on the accelerating-field-accelerating-length product. The maximum electron energy gain possible using a CO/sub 2/ laser running on 9.6- and 10.3- mu m wavelengths has been compared with the practical energy limit defined by the experimental limits of the machine.<>