Measurements of critical gradient behavior of fast-ion transport from Alfvén eigenmodes for predictive model development

C. S. Collins, W. W. Heidbrink, M. Podestà, R. B. White, G. J. Kramer, D. C. Pace, C. C. Petty, L. Stagner, M. A. Van Zeeland, Y. B. Zhu

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Experiments in the DIII-D tokamak show that many overlapping small-amplitude Alfvén eigenmodes (AEs) cause fast-ion transport that is consistent with the critical gradient paradigm. Measurements indicate a sudden increase in fast-ion transport in the presence of many simultaneous AEs at a threshold in neutral beam power corresponding to a threshold for orbit stochasticity [1]. The threshold varies in fast-ion phase space and is well above the AE linear stability threshold, meaning that some AEs can be tolerated before performance-degrading transport occurs. Above threshold, transport becomes stiff, resulting in virtually unchanged fast-ion density profiles despite increased beam drive. These studies are being used to develop a validated, predictive transport model that can efficiently calculate AE-induced transport and the resulting fast-ion profile over a wide parameter regime in order to design optimal fusion reactor scenarios that avoid undesirable AE-transport.

Original languageEnglish
Title of host publication44th EPS Conference on Plasma Physics, EPS 2017
EditorsA. Bret, M. Fajardo, E. Westerhof, A. Melzer, B. Dromey, C. Riconda
PublisherEuropean Physical Society (EPS)
ISBN (Print)9781510849303
StatePublished - 2017
Externally publishedYes
Event44th European Physical Society Conference on Plasma Physics, EPS 2017 - Belfast, United Kingdom
Duration: Jun 26 2017Jun 30 2017

Publication series

Name44th EPS Conference on Plasma Physics, EPS 2017

Conference

Conference44th European Physical Society Conference on Plasma Physics, EPS 2017
Country/TerritoryUnited Kingdom
CityBelfast
Period06/26/1706/30/17

Funding

*Work supported by U.S. Department of Energy under DE-FC02-04ER54698, DE-FG03-

FundersFunder number
U.S. Department of EnergyDE-FC02-04ER54698, DE-FG03-

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