Measurements of electron temperature and density of slow theta pinch plasma by laser scattering

Laser scattering is a very powerful diagnostic technique for the measurements of high temperature and high density plasmas. This method has been used in many experiments with successful results. Here 90° scattering is observed to determine the electron temperature and density of the slow theta pinch plasma of relatively large device, which had been used as a plasma source of BSG devices. The temperature and density are in the order of ∼ 10¹⁶ cm^-3 and ≲ 10 eV, respectively, so that the plasma is isothermal (τ_ie < 10^-6_sec), and then ion temperature, which ia more important for the experiment, can be estimated as well as electron temperature and density. The characteristics of theta pinch are : L=60 cm, d=10 cm, V=40 kV and E=11 kJ. The results of scattering theory are simply described for the understanding of experimental results. Observed scattered spectra were ranged from α=0.3 to 1.3 and electron temperature, from about 8 to 4 eV, according to experimental conditions. The time dependence of electron temperature and density was obtained in case of initial gas pressure of 35 mtorr. (author)