The paper describes an experimental method to carry out research of dynamics and macrostructure of optical multichannel discharges (time of exaltation τ ~ 10^-8c), both in atmosphere, and in vacuum (p~10-10² torr). In order to generate counter light erosive plasma-gas flows two targets were used representing aluminium film by depth 200 nm marked on the part of a backlash by magnetron sputtering on glass by depth 2 mm. The experimental definition of dynamics and macrostructure of polychannel lighterosive discharges is executed by a method of a polarization interferometry. These researches are necessary at analysis and mining of a broad band of photon powerplants high-density powers.