Time-resolved optical spectroscopy of high-temperature plasmas

Abstract

This invited talk describes spectroscopic studies of high-current plasma discharges within PF- and RPI-type facilities, used for basic and application-oriented research. Particular attention is paid to measurements of temporal changes of spectral lines from working gases and impurities. Time-resolved spectral measurements were carried out by means of a Mechelle(R)900 spectrometer, operating in the wavelength range from about 200 nm to 1100 nm, with exposition times varied from 100 ns up to 50 ms. That spectrometer was equipped with a cooled CCD camera coupled with a PC and GRAMS-32(R) software. Spectroscopic studies of the deuterium Balmer-lines and some impurity lines, as observed within the PF-360 experiment, are presented and discussed. Estimates of temporal changes in the electron concentration and temperature are given. Measurements of temporal changes in the emission of the deuterium- and impurity-lines emitted from a mega-joule PF-1000 facility are also described. Capabilities of optical techniques to study the interaction of PF discharges with different targets are discussed. Time-resolved spectroscopic studies of plasma discharges within the RPI-IBIS facility, used for material engineering, are also presented. Optical spectra, as recorded for different operational modes, are compared. The use of spectroscopic techniques to study the interaction of pulsed plasma-ion streams with different materials is considered. The presented results of research on dynamics of pulsed plasma streams (produced in different experimental facilities) as well as the described optical diagnostic techniques are important not only for basic physical studies but also for application-oriented research.