Laser polarization effect on ion acceleration in laser-cluster interaction

The interaction of high-intensity laser pulses with homo-nuclear aluminum clusters carried out by 2D3V UMPIC code has been investigated. The qualitative picture of the ion acceleration depends on the strength of the laser field and the cluster radius. In this study, the radius of the cluster and the laser dimensionless amplitude has been changed, and the effect of laser polarization on ion acceleration by these variations has been considered. Increasing cluster radius (from 10 to 200 nm), simulations show transferred laser energy to the ions increases for both linear and circular polarization, but the magnitude of this growth for circular polarization is larger than that of linear polarization in a given laser intensity. Also, the effect of laser dimensionless amplitude on ion acceleration has been studied for both laser polarizaton. Simulation reveals that aluminum ions cut-off energy and their energy spread increase rapidly up to a(0)similar to 2.5, and then saturate at larger amplitudes, for both polarizations. However, by increasing laser amplitude (a(0)>5), energy spread of linear polarization is less than that of circular polarization.