Experimental comparison of recycling and pumping changes during resonant magnetic perturbation experiments at low and high collisionality in DIII-D

E. A. Unterberg, N. H. Brooks, T. E. Evans, M. E. Fenstermacher, D. L. Hillis, R. Maingi, S. Mordijck, R. A. Moyer, T. H. Osborne, T. W. Petrie, J. G. Watkins

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10 Scopus citations

Abstract

Resonant magnetic perturbations (RMPs) have been shown to successfully suppress edge localized modes (ELMs) in the DIII-D tokamak. A previous study of target plate conditions highlighted differences in RMP discharges between low and high electron collisionality, νe*, operation in DIII-D. This paper reports on a systematic study of the electron density pump-out associated with the turn-on of the RMP over a wide range of operating conditions in DIII-D, including shapes and collisionalities similar to those anticipated in ITER. It is shown that the pump-out magnitude, Δne, has an upper envelope that is inversely proportional to the pedestal νe*. The particle decay times, which are calculated based on global D2 particle balances, show an increase as the pedestal νe* is increased. Both results are suggestive that the underlying physics mechanism is an increase in edge particle transport and/or that wall depletion is playing a role in the pump-out magnitude.

Original languageEnglish
Pages (from-to)486-489
Number of pages4
JournalJournal of Nuclear Materials
Volume390-391
Issue number1
DOIs
StatePublished - Jun 15 2009
Externally publishedYes

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