Imaging the Spatial Distribution of Microwave Intensity Using the Recombination Continuum Emitted by the Positive Column of the Cs–Xe DC Discharge

Abstract

We study experimentally the possibility of using the recombination continuum (RC) emitted by a nonequilibrium plasma of the positive column (PC) of a Cs–Xe discharge for real-time imaging of the spatial distribution of microwave intensity. A uniform plane slab of dense plasma of the PC of a Cs–Xe discharge with aperture 10×8 cm2 was used for the imaging. A continuous-wave (CW) magnetron was the microwave source with frequency 35.4 GHz and power up to 20 W. We measured the dependence of the RC intensity on the intensity of the microwaves incident on the plasma. Spatial distributions of the microwave intensity for a microwave beam and the H01 mode of a circular waveguide were imaged. The results of these experiments show that spatial distributions of microwave intensity measured using RC agree well with the distributions obtained using other methods. A temporal resolution of 10 μs was demonstrated and an energy-flux sensitivity of about 4·10-5 J/cm2 was achieved in the microwave-imaging experiments.