Acceleration of dense electron bunches by ultra-intense laser pulse

Summary form only given, as follows. The acceleration of the dense electron bunches at the front of a high-power electromagnetic wave in vacuum is considered in this paper. The computer simulation of this process was made with the help of numerical analytical 1D3V model where for the radiation friction force the analytical expression was used In this case the equations of motion are reduced to the system of ordinary differential equations with delay. It is shown that due to the action of the radiation friction force the bunching forces emerge. These forces compress the bunch in the longitudinal direction and support the initial geometry by slowing down the electrons with velocities larger than the mean velocity of the bunch and accelerating the delaying electrons. The lifetime of the bunch depends on the acceleration parameter a/sub o/, initial thickness of the target and electron density inside the bunch. As a result, all of the bunch electrons can be synchronously accelerated to ultra-relativistic velocities during the first several half-periods of the external electromagnetic field that can correspond to time intervals of hundreds of femtoseconds in the laboratory frame. The effective compression of the bunch during its interaction with ultra-intense laser pulse is also investigated. This compression results in considerable reducing the thickness of the bunch at the initial stage of acceleration.