Microwave radiation of cylindrical plasma column

Abstract

The travelling wave antennas representing a column of isotropic plasma and a plasma column placed into external infinitely large magnetic field have been theoretically and numerically investigated and compared. The relationships of radiation patterns as a function of the plasma density, geometrical parameters of the plasma cylinder and the radiation wavelength were also investigated. We considered both the linear antennas and the radiating antennas with wavelengths close to the antenna radius. An axially symmetric E-wave was studied. The need of taking into account the radial distribution of antenna current was shown. The dependence of normalized radiation patterns on the wave-slowing was analyzed. The characteristic value of plasma density was found; if this value is exceeded, the normalized radiation patterns are sharp directional and have the main lobe located at small angle towards the antenna axis. For the magnetized plasma this characteristic value of density is much smaller than for the isotropic one. With the rise of the plasma density the level of side lobes gets smaller.