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Implementation and assessment of an extended hydrogenic molecular model in UEDGE
Author(s) -
Holm A.,
Rognlien T.D.,
Meyer W.H.
Publication year - 2020
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.201900150
Subject(s) - collisionality , equipartition theorem , plasma , atomic physics , ion , electron , tokamak , molecule , deuterium , electron density , thermal , physics , materials science , nuclear physics , thermodynamics , magnetic field , quantum mechanics
Two sets of pure deuterium plasmas are simulated using UEDGE, one including atoms and molecules and the other including atoms only as separate fluid species. Simulation results in one and two dimensions are reported to assess the role of molecules in tokamak plasmas. It is shown that thermal coupling of the molecules to the plasma can be relevant for the onset of detachment under highly collisional conditions in simple geometries, but play a modest role at low collisionality. Ion‐molecule equipartition presents an additional ion energy loss channel, dissipating ion energy that would otherwise heat the electrons by equipartition. The resulting reduced electron temperature increases the ion‐electron recombination by an order of magnitude as the plasma density is increased, yielding earlier and deeper detachment.