Title: Turbulent particle transport as a function of toroidal rotation in DIII-D H-mode plasmas

Abstract

In this paper we show how changes in toroidal rotation, by controlling the injected torque, affect particle transport and confinement. The toroidal rotation is altered using the co- and counter neutral beam injection (NBI) in low collisionality H-mode plasmas on DIII-D with dominant electron cyclotron heating (ECH). We find that there is no correlation between the toroidal rotation shear and the inverse density gradient, which is observed on AUG when $${{T}_{\text{e}}}/{{T}_{\text{i}}}$$ is varied using ECH (Angioni et al 2011 Phys. Rev. Lett. 107 215003). In DIII-D, we find that in a discharge with balanced torque injection, the $$E\times B$$ shear is smaller than the linear gyrokinetic growth rate for small $${{k}_{\theta}}{{\rho}_{s}}$$ for $$\rho =0.6$$ –0.85. This results in lower particle confinement. In the co- and counter- injected discharges the $$E\times B$$ shear is larger or close to the linear growth rate at the plasma edge and both configurations have higher particle confinement. In order to measure particle transport, we use a small periodic perturbative gas puff. This gas puff perturbs the density profiles and allows us to extract the perturbed diffusion and inward pinch coefficients. We observe a strong increase in the inward particle pinch in the counter-torque injected plasma. Lastly, the calculated quasi-linear particle flux, nor the linear growth rates using TGLF agree with experimental observations.

Authors:

Wang, Xin ^[1]; Mordijck, Saskia ^[1]; Zeng, Lei ^[2]; Schmitz, Lothar ^[2]; Rhodes, Terry L. ^[2]; Doyle, Edward J. ^[2]; Groebner, Richard ^[3]; Meneghini, Orso ^[3]; Staebler, George M. ^[3]; Smith, Sterling P. ^[3]

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+ Show Author Affiliations

1. College of William and Mary, Williamsburg, VA (United States)
2. Univ. of California, Los Angeles, CA (United States)
3. General Atomics, San Diego, CA (United States)

Publication Date:

Tue Mar 01 00:00:00 EST 2016

Research Org.:

General Atomics, San Diego, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1350091

Alternate Identifier(s):

OSTI ID: 1239851

Grant/Contract Number:  

FC02-04ER54698; FG02-08ER54984; SC0007880

Resource Type:

Accepted Manuscript

Journal Name:

Plasma Physics and Controlled Fusion

Additional Journal Information:

Journal Volume: 58; Journal Issue: 4; Journal ID: ISSN 0741-3335

Publisher:

IOP Science

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; particle transport; ExB shear; turbulence