Propagation of intense relativistic sheet electron beam in periodic cusped magnetic fields

The propagation of a relativistic (300 keV) sheet electron beam carrying high current (3 kA) through the offset-pole periodic cusped magnetic fields with low amplitude (0.173 T) and short period (20 mm) has been investigated theoretically and numerically. The expressions of the space-charge fields with finite width of the waveguide are given, followed by the expressions of the transverse focusing forces acting on the sheet electron beam with finite thickness. The amplitude and the period of the offset-pole periodic cusped magnetic fields, as well as the width and height of the beam channel, are obtained through beam matching. The 3D-PIC simulations according to the theoretical results show that, the intense relativistic sheet electron beam could be well focused in the horizontal direction,