Electromagnetic-wave absorption in a plasma-loaded rectangular waveguide

Summary form only given. Collisional absorption of electromagnetic (EM) waves is being investigated using a plasma-loaded, rectangular C-band waveguide. In initial experiments, EM-wave-attenuation up to the 13-dB dynamic-range limit of the crystal detectors was demonstrated. A three-gap spark array generated an inhomogeneous plasma near the center of the slotted waveguide. The attenuation increased from 0 to 13 dB as the electron density was increased by raising the spark-gap current to 850 A. Collisional absorption was also investigated as a function of the shape of the plasma-density profile and the electron collision frequency. A 20-gap spark array was employed to generate different plasma-density profiles, and a tuned receiver was used to extend the dynamic range of the system to >40 dB