Characterization and focusing of laser-accelerated proton beams from hemisphere shells

In proton fast ignition, a focused proton beam with the diameter of 40 $\mu$m and the energy about 20kJ is required to deposit in the DT core within 20ps [1]. This proton beam can be produced using a hemisphere shell placed at the end of a hollow cone [2]. Recent experiments on the Trident Laser have demonstrated the production and focusing of proton beams in such a structure [3]. In this talk we will present the LSP simulation results on laser-accelerated proton beams from the hemisphere shells, where the laser-plasma interaction (LPI) package are self-consistently included. The general properties and conversion efficiency of the proton beams will be discussed and will be also compared with those from the previous LSP injection/excitation-model simulations. \\[4pt] [1] S. Atzeni et al., Phys. Plasmas 6, 3316 (1999).\\[0pt] [2] M. Roth et al., Phys. Rev. Lett. 86, 436 (2001).\\[0pt] [3] T. Bartal et al., submitted to Nature Phys (2011).