PLASMA IN A HIGH-POWER RELATIVISTIC GENERATOR RETARDING STRUCTURE

This work is dedicated to the problem of microwave radiation pulse len gth limitation in vacuum devices based on high-power relativistic elec tron beams (REB). The experiments were performed using a 500 keV, 3 ke V, 1 mu s REB with no plasma at the accelerator cathode, diaphragm, or beam collector. Optical, X-ray, and other diagnostics were used. The cause of the pulsed microwave emission premature cut-off armed out to be the microwave breakdown in the generator retarding structure. The b reakdown was initiated by the retarding structure wall bombardment wit h either primary-beam, or secondary electrons (i.e., REB electrons bac kscattered from the collector).