Spatial profiles of neutral and charged particles in the negative glow region of abnormal discharges in argon and their interpretation
Investigations of the negative glow plasma in a dc-discharge in argon are described. The discharge was produced between circular titanium electrodes (R = 3 cm), at a distance of 10 cm, in a vacuum vessel of about 30 cm diameter. UHV-conditions and ultra-pure gas were essential. The discharge was operated at pressures between 0.2 mbar and 0.1 mbar, at currents of 5 mA and 10 mA corresponding to voltages between 0.5 kV and 2 kV. By the use of Langmuir probes and of laser induced fluorescence it has been possible to determine the absolute densities of the two electron groups, of the metastable A-atoms and of the neutral and ionised Ti-atoms. For at least one set of parameters, the radial and spatial distributions of these particles have also been determined. By choosing optimum discharge parameters, conditions are established such that an approximate interpretation of the observed density ratios seems possible. The axial profile of the electric field has also been measured and can be related to the observed density profiles of ions and electrons.
Bibliographic Reference: Article: Proceedings of the 5th International Symposium on Laser-Aided Plasma Diagnostics (1991) p. 52
Record Number: 199111655 / Last updated on: 1994-12-02
Original language: en
Available languages: en