Laser-driven proton acceleration from a near-critical density target

The duration-controlled amplified spontaneous emission with intensity of 1013W/cm2 is used to convert a 7.5 μm thick polyimide foil into a near-critical plasma, in which the p-polarized, 45 fs, 1019 W/cm2 laser pulse generates 3.8 MeV protons, emitted at some angle between the target normal and the laser propagation direction of 45°. The mechanism which explains the proton generation from the near-critical plasma cloud is discussed using the two-dimensional (2D) particle-in-cell (PIC) simulation.