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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:
 [1];  [1];  [2];  [2];  [2];  [2];  [3];  [3];  [3];  [3]
  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:
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:
Journal Article: 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

Citation Formats

Wang, Xin, Mordijck, Saskia, Zeng, Lei, Schmitz, Lothar, Rhodes, Terry L., Doyle, Edward J., Groebner, Richard, Meneghini, Orso, Staebler, George M., and Smith, Sterling P. Turbulent particle transport as a function of toroidal rotation in DIII-D H-mode plasmas. United States: N. p., 2016. Web. doi:10.1088/0741-3335/58/4/045026.
Wang, Xin, Mordijck, Saskia, Zeng, Lei, Schmitz, Lothar, Rhodes, Terry L., Doyle, Edward J., Groebner, Richard, Meneghini, Orso, Staebler, George M., & Smith, Sterling P. Turbulent particle transport as a function of toroidal rotation in DIII-D H-mode plasmas. United States. doi:10.1088/0741-3335/58/4/045026.
Wang, Xin, Mordijck, Saskia, Zeng, Lei, Schmitz, Lothar, Rhodes, Terry L., Doyle, Edward J., Groebner, Richard, Meneghini, Orso, Staebler, George M., and Smith, Sterling P. Tue . "Turbulent particle transport as a function of toroidal rotation in DIII-D H-mode plasmas". United States. doi:10.1088/0741-3335/58/4/045026. https://www.osti.gov/servlets/purl/1350091.
@article{osti_1350091,
title = {Turbulent particle transport as a function of toroidal rotation in DIII-D H-mode plasmas},
author = {Wang, Xin and Mordijck, Saskia and Zeng, Lei and Schmitz, Lothar and Rhodes, Terry L. and Doyle, Edward J. and Groebner, Richard and Meneghini, Orso and Staebler, George M. and Smith, Sterling P.},
abstractNote = {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.},
doi = {10.1088/0741-3335/58/4/045026},
journal = {Plasma Physics and Controlled Fusion},
issn = {0741-3335},
number = 4,
volume = 58,
place = {United States},
year = {2016},
month = {3}
}

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