Nonthermal relativistic electron acceleration due to laser-induced incoherent wakefields with external static magnetic fields

Wakefield acceleration has been considered as a candidate of the origin of cosmic rays and the electron power-law spectra with an index of −2 and it has been demonstrated experimentally and numerically. In order to further support the universality of wakefield acceleration to address the power-law spectra of cosmic rays, we investigate the nonthermal acceleration of relativistic electrons due to the laser-induced wakefield acceleration with a static external magnetic field using two-dimensional particle-in-cell simulation.The results indicate that the power-law spectra with an index of −2 still remain even in the presence of external magnetic field.