Improvements in the Microwave Propagation Method of Studying Decaying Gas Plasmas

Some improvements in measuring the transient values of the electron density in decaying gas plasmas by the propagation method are described. The electron density, as is known, can be calculated from measurements of phase shift and attenuation of a probing microwave signal propagated through the plasma. The increase of the detection sensitivity of very small phase shifts (X-band microwave) leads to at least a tenfold decrease in electron density measurement. Thus, in a ten-inch long discharge tube densities of 1011−108 cm−3 are measured, which is comparable to that by the cavity method at the same frequency.