Impact of Resonant Magnetic Perturbations on Zonal Flows and Microturbulence

Authors

• Z. R. Williams, Hope CollegeFollow
• M. J. Pueschel, The University of Texas at Austin
• P. W. Terry, University of Wisconsin-Madison
• T. Nishizawa, University of Wisconsin-Madison
• D. M. Kriete, UW-Madison College of Engineering
• M. D. Nornberg, University of Wisconsin-Madison
• J. S. Sarff, University of Wisconsin-Madison
• G. R. McKee, UW-Madison College of Engineering
• D. M. Orlov, University of California, San Diego
• S. H. Nogami, West Virginia University

Document Type

Article

Publication Date

9-1-2020

Publication Source

Nuclear Fusion

Volume Number

60

Issue Number

9

ISSN

00295515

E-ISSN

17414326

Article Number

096004

Abstract

Results from a joint experimental and computational effort studying the effect of resonant magnetic perturbations (RMPs) on microturbulence levels and their connection to zonal flows in the DIII-D tokamak L-mode are presented. Beam emission spectroscopy measurements show a direct increase in density fluctuations at microturbulent scales with increasing RMP amplitude, suggesting that magnetic activity introduced by the RMP affects the regulation of microturbulence on DIII-D. This is analogous to how MHD-scale magnetic fluctuations arising from tearing modes have been observed in simulations to increase microturbulence levels in the reversed-field pinch (RFP). In the RFP, this is attributed to magnetic fluctuations eroding turbulence-limiting zonal flows; this work examines if a similar mechanism is present for DIII-D microturbulence. Gyrokinetic simulations find that the application of an RMP corresponds directly to a decrease in zonal flow levels, producing a similar increase of turbulent fluctuation levels over a range of RMP amplitudes as observed in the experiment.

Keywords

microturbulence, resonant magnetic perturbations, tokamak, transport, turbulence, zonal flows

Recommended Citation

Published in: Nuclear Fusion, Volume 60, Issue 9, September 1, 2020.