Highly efficient acceleration and collimation of high-density plasma using laser-induced cavity pressure

An efficient scheme of acceleration and collimation of dense plasma is proposed and examined. In the scheme, a target placed in a cavity coupled with a guiding channel is irradiated by a laser beam introduced into the cavity through a hole and accelerated along the channel by the pressure of the ablating plasma confined in the cavity. Using 1.315 μm, 0.3 ns laser pulse of energy up to 200 J and a thin CH target, it was shown that the energetic efficiency of acceleration in this scheme is an order of magnitude higher than in the case of conventional ablative acceleration.