Observations of the effect of magnetic fields on the radiation from plasma-covered antennas

Measurements of the broadside radiation from an anisotropic plasma-covered slot are compared with theoretical predictions which neglect input impedance changes and coupling to electroacoustic or Tonks-Dattner resonances. For a magnetic field normal to the plasma layer, the results demonstrate transmission enhancement and underscore the necessity of a strong field ( ). They also highlight some of the limitations of existing theoretical treatments. In particular, it is concluded that collisional damping, impedance variations, and electroacoustic resonances must be included for an accurate prediction of magnetic field effects. The experimental system consists of a narrow aperture in a large ground screen covered by a bank of long discharge tubes which are collectively equivalent to a plane layer. All measurements are performed at a fixed frequency of 565 Mc during the afterglow of the pulsed discharge.