The Emission of Intense Microwave Radiation from Superlimiting Currents.
A 0.8 MeV electron beam has been injected through thin foils into a vacuum drift space, with no applied magnetic fields. The injected current has been varied from 5 to 25 kA by adjusting the anode-cathode gap and anode aperture size. The space charge limited current for the system has been measured to be 12 kA. Several megawatts of microwave emission are observed when the diode current exceeds the limiting current. Properties of the diode, the transmitted beam, and the microwave emission have been studied. The emission process may be either oscillation of the virtual cathode which forms in the drift space, or reflexing of electrons, bunched by the negative mass instability, between the cathode and the virtual cathode.
- Pub Date:
- June 1981
- Physics: Fluid and Plasma