In radiation pressure dominated laser ion acceleration schemes, transverse target deformation and Rayleigh-Taylor (RT)-like instability always develop quickly, break the acceleration structure, limit the final accelerated ion energy, and lower the beam quality. To overcome these issues, we propose a target design named dual parabola targets consisting of a lateral thick part and a middle thin part, each with a parabolic front surface of different focus positions. By using such a target, through interactive laser and target shaping processes, the central part of the thin target will detach from the whole target and a microtarget is formed. This enables the stable acceleration of the central part of the target to high energy with high quality since usual target deformation and RT-like instabilities with planar targets are suppressed. Furthermore, this target design reduces the laser intensity required to optimize radiation pressure acceleration by more than 1 order of magnitude compared to normal flat targets with similar thickness and density. Two-dimensional particle-in-cell simulations indicate that a quasimonoenergetic proton beam with peak energy over 200 MeV and energy spread around 2% can be generated when such a solid target (with density 400nc and target thickness 0.5λ0) is irradiated by a 100 fs long circularly polarized laser pulse at focused intensity IL∼9.2×1021 W/cm2.
|Number of pages||10|
|Journal||Physical Review Special Topics: Accelerators and Beams|
|Publication status||Published - 5 Dec 2013|
- ion acceleration
- proton beams
- target shaping