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Influence of Neutral Gas Fueling on Edge Instabilities in the Scrape‐Off Layer of TEXTOR‐94
Author(s) -
Reiser D.,
Tokar' M.Z.
Publication year - 2002
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 - 10.1002/1521-3986(200204)42:2/4<401::aid-ctpp401>3.0.co;2-k
Subject(s) - ballooning , toroid , atomic physics , plasma , radiative transfer , enhanced data rates for gsm evolution , perturbation (astronomy) , materials science , physics , mechanics , computational physics , tokamak , nuclear physics , optics , telecommunications , quantum mechanics , computer science
Strong neutral gas fueling in discharges with radiative improved confinement in TEXTOR‐94 is always accompanied by a considerable degradation of energy confinement, whereas moderate fueling permits to maintain the desirable features of this operational regime. Model calculations indicate that an additional edge transport effect has to be taken into account for scenarios with strong gas puffing to match the experimental observations. The suggestion that the impact of localized neutral gas distributions on high toroidal mode number ballooning‐type edge instabilities might be responsible for the enhanced edge transport is investigated and it is shown that the linear perturbation analysis indeed exhibits a pronounced effect depending on the strength of the puff rate and on the position of the neutral puff as well. Mixing length estimates provide transport coefficients of the expected order of magnitude serving a possible explanation for the experimentally found effects.