Mainz 1997 – wissenschaftliches Programm
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P: Plasmaphysik
P 22: Plasmadiagnostik IV
P 22.2: Vortrag
Donnerstag, 6. März 1997, 14:15–14:30, P 11
Detection of Atomic H and N in Expanding Plasmas produced by a Cascaded Arc — •H.F. D"obele2, G.J. Brinkman1, S. Mazouffre1, M.G.H. Boogaarts1, J.A.M. van der Mullen1, and D.C. Schram1 — 1Department of Applied Physics, Eindhoven University of Technology, P.O.Box 513, 5600 MB Eindhoven, The Netherlands — 2Institut f"ur Laser- und Plasmaphysik, Universit"at GH Essen, Universit"atsstr.5, D-45117 Essen
Two-photon Absorption Laser Induced Fluorescence measurements were performed on expanding plasmas consisting of argon/hydrogen and argon/nitrogen mixtures. Radial and axial density and temperature profiles of the atomic species were obtained. The argon/hydrogen plasma consists of a 6:1 mixture of Ar and H2. The measured temperatures were in the range of 500-3500 K. The axial density measurements show a fast decay with a characteristic length of 4 mm. Radial scans show for the density a Gaussian-like shape with a clear maximum in the centre and for the temperature a plateau in the centre with the temperature falling down at the edges. The amount of H-atoms is conserved during expansion. For measurements on nitrogen a plasma was used with only a small fraction of Ar (about 1%). Axial scans show a steep fall of density and temperature right after the nozzle. The temperature and density profiles indicate a shock region around 100 mm from the nozzle.