SPECTROSCOPIC DIAGNOSTICS OF PULSED PLASMA FLOW

Abstract

This paper presents the results of spectroscopic diagnostics of pulsed plasma flow. A pulsed plasma flow is generated when energy is carried to system of coaxial electrodes from capacitor banks. To obtain and investigate the spectral lines, spectrometer Solar S100 and a monochromator M833 was used. To determine the electron density in a pulsed plasma flow, the Stark broadening method of spectral lines was used. In the plasma, where the density of electrons and ions is high, there is a long-range Coulomb force. As a consequence, the use of Stark broadening is permissible for interacting charged particles of electrons and ions. The experiment was performed at different discharge powers and helium, hydrogen gas pressures. The obtained spectrograms showed the appearance of hydrogen lines Hα and Hβ. The output of the spectral lines of hydrogen occurs on permanent water molecules in a vacuum chamber or on an insulator. The method of relative intensities of spectral lines was applied to determine the temperature of the electrons of pulsed plasma flow. On the basis of the obtained results, brief theoretical descriptions of the dependences of the density and temperature of the electrons on the discharge voltage were investigated and given in this work. The spectral lines of Hα and Hβ were used to determine the temperature of the electrons by the method of relative intensities of the spectral lines. Also in experiments in the spectrum taken from the side windows of the experimental setup, the appearance of copper lines between the wavelengths of the order of 200–350 nm was observed. This shows that during the interaction of pulsed plasma with copper electrodes, the erosion of the material occurs.

Keywords: pulsed plasma accelerator, pulsed plasma flow, spectroscopic diagnostics.