A model of the saturation of coupled electron and ion scale gyrokinetic turbulence

G. M. Staebler, N. T. Howard, J. Candy, C. Holland

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

A new paradigm of zonal flow mixing as the mechanism by which zonal E × B fluctuations impact the saturation of gyrokinetic turbulence has recently been deduced from the nonlinear 2D spectrum of electric potential fluctuations in gyrokinetic simulations. These state of the art simulations span the physical scales of both ion and electron turbulence. It was found that the zonal flow mixing rate, rather than zonal flow shearing rate, competes with linear growth at both electron and ion scales. A model for saturation of the turbulence by the zonal flow mixing was developed and applied to the quasilinear trapped gyro-Landau fluid transport model (TGLF). The first validation tests of the new saturation model are reported in this paper with data from L-mode and high-β p regime discharges from the DIII-D tokamak. The shortfall in the predicted L-mode edge electron energy transport is improved with the new saturation model for these discharges but additional multiscale simulations are required in order to verify the safety factor and collisionality dependencies found in the modeling.

Original languageEnglish
Article number066046
JournalNuclear Fusion
Volume57
Issue number6
DOIs
StatePublished - May 9 2017
Externally publishedYes

Funding

This work was supported by the U.S. Department of Energy under DE-FG02-95ER54309, DE-FC02-04ER54698 and DE-FC02-08ER54963.

Keywords

  • L-mode transport shortfall
  • gyrokinetic turbulence
  • multi-scale transport
  • tokamak transport
  • zonal flows

Fingerprint

Dive into the research topics of 'A model of the saturation of coupled electron and ion scale gyrokinetic turbulence'. Together they form a unique fingerprint.

Cite this