Experimental studies of plasma effects on microwave signals

Summary form only given. The Plasma Physics Program of the US Air Force Office of Scientific Research is currently sponsoring an array of laboratory research efforts to precisely characterize the effects of plasma volumes on microwave signal propagation. Theory predicts strong microwave absorption and/or scattering by properly tailored plasma structures. The goal of this program is to compare these predictions with precise data gathered from actual laboratory systems with interesting parameter ranges. Scharer, Roth, and Brandenburg are concentrating on magnetized plasmas. These will rely on electron cyclotron resonance absorption to disrupt the microwave signal. Santoru and Destler are looking at collisional absorption in unmagnetized plasmas. Signal refraction and scattering will be evaluated by all the above. Alexeff is attempting to use a rapidly advancing plasma front to Doppler upshift the signal. Kuo is taking yet another tack by examining EM scattering from a filamentary plasma. The various studies encompass plasma densities from 10⁹ to 10¹⁴ per cm³ , magnetic fields up to 1 T, and microwave frequencies from 0.9 to 15.0 GHz