Two laser scattering systems based on Nd-glass laser and avalanche photodiodes are proposed. First system is designed for observation of radial profiles of the electron plasma density and temperature. Each of its 2–4 spectral modules consists of 25 spatial channels and includes a bandpass interference filter, low F-number camera lens, and 25-channel linear array of the avalanche photodiodes followed by amplifiers and ADCs. Every of 25 spatial channel can view the plasma volume with an adjustable length of 1.5–15 mm along the radius of a trap. In the IR spectral region the plasma background radiation is small and the main source of noise is the amplifier noise, which permits in this case observation of a plasma of a density of 1012 cm−3 with the S/N >60.
The second system is intended for measuring the longitudinal ne and Te profiles and uses the LIDAR technique, which is more suitable for open traps than for large tokomaks due to considerable larger axial length. A relative simple short pulse version of the probe laser (0.5–1 ns, 10 J), commercially available high speed APD-preamplifier modules, and ADC, as well as very high contrast-interference filters can provide longitudinal measurements with the spatial resolution 1 ≤·20 cm and S/N > 40 for ne ⩾1012 cm−3
The probe laser (30J, 8 ns, 1.06