The REB pulse-periodic microwave generators

The problem related to creating the high-power microwave generators based on high-current relativistic electron beams of a high pulse repetition frequency are studied. A short description of a pulse-periodic accelerator and investigation results for a vacuum diode are presented. A screening effect of emission site-leader space charge on a cathode surface is shown. In coaxial vacuum diodes this effect leads to a dependence of the site number on the external magnetic field and to a complemental increase of the beam electron transverse velocities that limits a generation effectiveness for a relativistic carcinotron in low magnetic fields. Experimental results of the investigation are presented and forming mechanism for the electron load in a high-frequency generator that define a limit for the microwave-radiation pulse length at a power level ≳ 10⁸ W is suggested.