HIGH-POWER RADIO-FREQUENCY GENERATION IN A HOLLOW-CATHODE DISCHARGE

High-power rf oscillations are obtained in a resistive load installed in the external electrical circuit of a low-pressure magnetic-field-free hollow-cathode discharge. These intense rf oscillations have been shown to be due to a collisionless instability of the cathode sheath. A very simple device based on this effect is shown to serve as a convenient and powerful rf oscillator. Typical results first achieved without any optimization, for frequencies of 20-30 MHz and load resistances of several tens of ohms, are as follows: power of about 5 kW and efficiency ∼25%.© 1995 American Institute of Physics.