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Transport of neutral atomic hydrogen in a supersonic plasma jet.
Author(s) -
Mazouffre S.,
Boogaarts M.G. H.,
Der Mullen J.A. M.,
Schram D. C.
Publication year - 1999
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1999.tb08783.x
Subject(s) - atomic physics , supersonic speed , hydrogen , jet (fluid) , plasma , chemistry , shock (circulatory) , coupling (piping) , excitation , scattering , physics , materials science , mechanics , optics , medicine , organic chemistry , quantum mechanics , metallurgy
In a supersonically expanding plasma jet created by a cascaded arc from an Ar‐H 2 mixture, spatially resolved densities, temperatures, and velocities of ground state atomic hydrogen are obtained by applying two‐photon excitation laser induced fluorescence. The axial velocity profile of H indicates a strong coupling between Ar and H atoms and it can be fully described in terms of a supersonic expansion model. However, whereas H atoms temperature profiles along the jet centerline clearly reveal the presence of a normal shock front, the atomic hydrogen density profiles do not. From the absence of a density jump across the normal shock front, it is conclude that the atomic hydrogen flux in the axial direction is not conserved. There are several indications that the coupling between H and Ar atoms is lost in the course of the expansion and that hydrogen atoms can escape the supersonic domain by a scattering process due to their large mean free path.