Loading...
Particle transport in low-collisionality H-mode plasmas on DIII-D
Mordijck, Saskia Wang, X. Doyle, E. J. Rhodes, T. L.
Mordijck, Saskia
Wang, X.
Doyle, E. J.
Rhodes, T. L.
Abstract
In this paper we show that changing from an ion temperature gradient (ITG) to a trapped electron mode (TEM) dominant turbulence regime (based on linear gyrokinetic simulations) results experimentally in a strong density pump-out (defined as a reduction in line-averaged density) in low collisionality, low power H-mode plasmas. We vary the turbulence drive by changing the heating from predominantly ion heated using neutral beam injection to electron heated using electron cyclotron heating, which changes the T-e/T-i ratio and the temperature gradients. Perturbed gas puff experiments show an increase in transport outside rho = 0.6, through a strong increase in the perturbed diffusion coefficient and a decrease in the inward pinch. Linear gyrokinetic simulations with TGLF show an increase in the particle flux outside the mid-radius. In conjunction an increase in intermediate-scale length density fluctuations is observed, which indicates an increase in turbulence intensity at typical TEM wavelengths. However, although the experimental changes in particle transport agree with a change from ITG to TEM turbulence regimes, we do not observe a reduction in the core rotation at mid-radius, nor a rotation reversal.
Description
Date
2015-11-01
Journal Title
Journal ISSN
Volume Title
Publisher
Collections
Download Dataset
Rights Holder
Usage License
Embargo
Research Projects
Organizational Units
Journal Issue
Keywords
Citation
Advisor
Department
Computer Science
DOI
https://doi.org/10.1088/0029-5515/55/11/113025