OPTICAL METHODS FOR HELICON DISCHARGE PLASMA PARAMETERS MEASUREMENT
The paper presents results of the helicon discharge plasma parameters measurements using optical diagnostic methods at the PN-3 facility. The description of the diagnostic complex is given. Plasma parameters measuring methods, including emission spectroscopy and laser-induced fluorescence, and methods for results processing are considered. The measurements were carried out in experiments to study the dependence of the helicon discharge plasma parameters on the magnitude of the magnetic induction and the profile of the magnetic field under the helicon antenna. The installation working gas was argon. Optical emission spectroscopy method was used to measure the electron temperature radial distribution for different parts of the plasma column. To determine the local concentration of singly ionized argon ion Ar II, we used the laser-induced fluorescence method using the 3d2G9 / 2 and 4p2F7/2 states. The optimal value of the magnetic field under the HF antenna, in terms of plasma profile and plasma density, was determined. Based on the results of the work it amounted to 900-1000 Gauss. The optimal configuration of magnetic field of the installation appears to be magnetic trap.