Model of self-generated magnetic field generation from relativistic laser interaction with solid targets

Abstract

Generation of self-generated annular magnetic fields at the rear side of a solid target driven by relativistic laser pulse is investigated by using theoretical analysis and particle-in-cell simulations. The spatial strength distribution of magnetic fields can be accurately predicted by calculating the net flow caused by the superposition of source flow and return flow of hot electrons. The theoretical model established shows good agreement with the simulation results, indicating that the magnetic-field strength scales positively to the temperature of hot electrons. This provides us a way to improve the magnetic-field generation by using a micro-structured plasma grating in front of the solid target. Compared with that for a common flat target, hot electrons can be effectively heated with the well-designed grating size, leading to a stronger magnetic field. The spatial distribution of magnetic fields can be modulated by optimizing the grating period and height as well as the incident angle of the laser pulse.