We present a theoretical and numerical study of the novel acceleration scheme by applying a combination of laser radiation pressure and shielded Coulomb repulsion in laser acceleration of protons in multi-species gaseous targets. By using a circularly polarized CO2 laser pulse with a wavelength of 10 μm, much greater than that of a Ti:Sapphire laser, the critical density is significantly reduced, and a high-pressure gaseous target can be used to achieve an overdense plasma. This gives us a larger degree of freedom in selecting the target compounds or mixtures, as well as their density and thickness profiles. By impinging such a laser beam on a carbon-hydrogen target, the gaseous target is first compressed and accelerated by radiation pressure until the electron layer disrupts, after which the protons are further accelerated by the electron-shielded carbon ion layer. An 80 MeV quasi-monoenergetic proton beam can be generated using a half-sine shaped laser beam with peak power 70 TW and pulse duration of 150 wave periods.
- gaseous targets
- laser accelerated protons
- laser acceleration
Liu, T-C., Shao, X., Liu, C-S., Eliasson, B., Hill III, W. T., Wang, J., & Chen, S-H. (2015). Laser acceleration of protons using multi-ion plasma gaseous targets. New Journal of Physics, 17(2), . https://doi.org/10.1088/1367-2630/17/2/023018