Measurement of Temperature and Density Profiles of the Plasma at PR-2 Facility

A new system of probe diagnostics at linear plasma simulator PR-2 is described, allowing us to measure the profiles of plasma temperature and density in different cross sections of the plasma column. The Langmuir probe fixed to the movable part of the two-coordinate positioning system built into the PR-2 passes the region of the discharge area during the process of measuring plasma parameters. The overall dimensions of the positioning system make it possible to mount electrical probes (magnetic probes, optical fibers, and other diagnostic equipment) covering almost the entire volume of the vacuum chamber between the magnetic mirrors of the device. We present the measurement results of local plasma parameters of the beam-plasma discharge (BPD) for different values of the input power and working gas pressure. The boundaries of appearance of discharge of three types were determined: the diffusive BPD mode, the BPD mode, and the arc mode. Dependences of the plasma concentration and temperature on the input power for different values of pressure have been also determined.