Energy transfer in the plasma wake-field accelerator

A computer simulation of the transfer of energy from the driving beam to the trailing beam in the plasma wake-field accelerator is performed. The beam-plasma system is simulated using a one-and-two-halves-dimensional relativistic, electromagnetic particle code. It is shown that with an asymmetric current distribution in the driving bunch, the energy transfer is found to be as high as 70 percent, or approximately 1 GeV. Good agreement is found with theoretical predictions. It is indicated that the observed degradation in energy gain is caused by the relative phase change slippage and the two-stream instability. It is suggested that as far as the transformer ratio is concerned, the finite transverse size of a driving beam should not alter the present physical model. (R.R.)