The controllable super-high energetic electrons by external magnetic fields at relativistic laser-solid interactions in the presence of large scale pre-plasmas

Abstract

The two stage electron acceleration model [arXiv: 1512.02411 and arXiv: 1512.07546] is extended to the study of laser magnetized-plasmas interactions at relativistic intensities and in the presence of large-scale preformed plasmas. It is shown that the cut-off electron kinetic energy is controllable by the external magnetic field strength and directions. Further studies indicate that for a right-hand circularly polarized laser (RH-CP) of intensity $10^{20}\text{W}/{\text{cm}}^2$ and pre-plasma scale length $10\mu \text{m}$, the cut-off electron kinetic energy can be as high as $500\text{MeV}$, when a homogeneous external magnetic field of exceeding $10000\text{T}$ (or $B={\omega }_c/{\omega }_0>1$) is loaded along the laser propagation direction, which is a significant increase compared with that $120\text{MeV}$ without external magnetic field. A laser front sharpening mechanism is identified at relativistic laser magnetized-plasmas interactions with $B={\omega }_c/{\omega }_0>1$, which is responsible for these super-high energetic electrons.

4 pages, 4 figures