The Cascaded Arc: High Flows of Rovibrationally Excited H{sub 2} and its Impact on H{sup -} Ion Formation
- Department of Applied Physics, Plasma and Materials Processing, Eindhoven University of Technology (Netherlands)
The cascaded arc is a plasma source providing high fluxes of excited and reactive species such as ions, radicals and rovibrationally excited molecules. The plasma is produced under pressures of some kPa in a direct current arc with electrical powers up to 10 kW. The plasma leaves the arc channel through a nozzle and expands with supersonic velocity into a vacuum-chamber kept by pumps at low pressures. We investigated the case of a pure hydrogen plasma jet with and without an applied axial magnetic field that confines ions and electrons in the jet. Highly excited molecules and atoms were detected by means of laser-induced fluorescence and optical emission spectroscopy. In case of an applied magnetic field the atomic state distribution of hydrogen atoms shows an overpopulation between the electronic states p = 5, 4 and 3. The influence of the highly excited hydrogen molecules on H{sup -} ion formation and a possible mechanism involving this negative ion and producing atomic hydrogen in state p = 3 will be discussed.
- OSTI ID:
- 21269103
- Journal Information:
- AIP Conference Proceedings, Vol. 1097, Issue 1; Conference: 1. international symposium on negative ions, beams and sources, Aix-en-Provence (France), 9-12 Sep 2008; Other Information: DOI: 10.1063/1.3112517; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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