Kiel 2004 – scientific programme

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P: Plasmaphysik

P 3: Postersitzung: Niedertemperaturplasmen Plasmatechnologie I, Diagnostische Methoden I

P 3.27: Poster

Monday, March 8, 2004, 17:45–19:30, Foyer

Generation of negative hydrogen ions in a magnetic multipole plasma source with combined inductive and capacitive high frequency excitation — •Thomas Mosbach, H.-M. Katsch, and H.F. Döebele — Universität Duisburg-Essen, Standort Essen, Institut für Experimentelle Physik, D-45117 Essen

Negative hydrogen and deuterium ions extracted from plasma sources have the potential for high-current charged and neutral particle beams for accelerator systems. Negative ions in the MeV energy range are of particular relevance for neutral beam plasma heating in fusion devices. Magnetic multipole plasma sources with filaments have been found to have a high content of negative ions. Plasma ion sources for long-term operation in fusion related research require, however, electrodeless excitation for various reasons. Inductively excited plasma sources generate ions but due to the absence of a high-energetic electronic component in the EEDF those sources do not operate at optimum. A combined inductive and capacitive high frequency excitation has the perspective to obtain both a high plasma density and high-energy electrons. The high-energy electron group provides a suprathermal population of the rovibronic states of the hydrogen molecules in the electronic ground state. Dissociative attachment of low-energy electrons to the molecules leads to the desired negative ions. We present results on the detection of vibrationally excited electronic ground-state molecules by laser induced fluorescence with VUV radiation.

This work is supported by the Deutsche Forschungsgemeinschaft DFG.