Experimental Study of Inhomogeneous Reflex-Discharge Plasma Using Microwave Refraction Interferometry

The phase shift at the plasma interferometry with oblique microwaves and microwaves passing through the center of a plasma formation has been calculated. The critical density Ncr and the critical radius rcr of a plasma layer, at which microwaves do not hit the horn antenna, are calculated for various radial plasma distribution functions. The time dependences of the phase shift for the transverse and oblique probing modes are experimentally measured. Using the phase shifts determined by the both methods, the time dependence of the product NpL of the electron concentration in plasma and the optical path length of a microwave beam in vacuum is found, and the average plasma density is estimated.