Generation of collimated beams of relativistic ions in laser-plasma interactions

A method is proposed for generating collimated beams of fast ions in laser- plasma interactions. Two-dimensional and three-dimensional particle-in-cell simulations show that the ponderomotive force expels electrons from the pl asma region irradiated by a laser pulse. The ions with unneutralized electr ic charge that remain in this region are accelerated by Coulomb repulsive f orces. The ions are focused by tailoring the target and also as a result of pinching in the magnetic field produced by the electric current of fast io ns. (C) 2000 MAIK "Nauka/Interperiodica".