A PARTICLE-IN-CELL SIMULATION OF NONLINEAR AMPLIFICATION OF INVERSE BREMSSTRAHLUNG ELECTRON ACCELERATION

An electromagnetic particle-in-cell simulation code is used to study t he mechanism of nonlinear amplification of inverse Bremsstrahlung elec tron acceleration. We find that the self-consistent space-charge field decreases only slightly the net energy gain. Previous results from si ngle-particle or approximated self-field calculations are recovered in the appropriate limits. Furthermore, the simulation has also shown th at, if the particles are launched into the interaction region as a pre -bunched particle beam, the average energy gain of the beam becomes mu ch larger than that obtained when the particles are uniformly distribu ted along the laser wavelength lambda.