Microwave Generation in Air and Vacuum

This paper describes two sets of experiments. In the first set, the ultraviolet radiation produced by the spark channel creates the photoionized plasma in air between two parallel plates. The spatial resonator formed between the two plates generates many microwave lines that are recorded by the E-field probe. Comparison is made between these results and the data obtained in the experiments done in vacuum using the electron beam. In the second set of experiments, some details of the microwave generation in atmospheric air and argon are presented. The frequency lines arising from the simple spatial resonator and from the resonant cavity are observed and recorded. The electrons are generated by the electric field and by the photoionization. Comparison between the data leads to the suggestion of the possibility to enhance the microwave power level in the plasma-assisted slow-wave oscillator.