Analytical model for ion acceleration by high-intensity laser pulses.

We present a general expression for the maximum ion energy observed in experiments with thin foils irradiated by high-intensity laser pulses. The analytical model is based on a radially confined surface charge set up by laser accelerated electrons on the target rear side. The only input parameters are the properties of the laser pulse and the target thickness. The predicted maximum ion energy and the optimal laser pulse duration are supported by dedicated experiments for a broad range of different ions.