Broadband attenuation of microwave by hollow cathode discharge plasma

Summary form only given. The absorption and scattering of microwaves by a structured arc plasma produced inside a bell jar vacuum chamber were studied. Argon plasma was produced in a background pressure of 1 to 10 torr through a steady-state hollow-cathode discharge. The plasma was shown to give rise to strong absorption and scattering of incident microwaves. The difference between the intensities of received signals with and without plasma suggests the attenuation of the test wave by the plasma. Over a very wide frequency band of 4-12 GHz, a greater than 20-35-dB attenuation of the transmitted waves was measured. The attenuation was mainly caused by scattering rather than by absorption, because of the small size of the plasma. There was also no measurable enhancement in the reflected signal