Study of 200kA REB focussing depending on the “Kalmar” diode geometry

High-power relativistic electron beam focussing represents an important problem to be solved in order to make the controlled pulsed electron fusion feasible. As shown by L. I. Rudakov [1, 2], a relativistic electron beam with a current 10⁷A and a power density. in the beam 10¹³W/cm² is required. The “Kalmar-1” accelerator, producing a relativistic electron beam with a 5·10¹¹ – 5·10¹²W/cm² power density, is described. The results on the relativistic electron beam focussing as a function of electrode geometry and voltage prepulse in the high-voltage diode are presented.