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Title: Testing neoclassical and turbulent effects on poloidal rotation in the core of DIII-D

Experimental tests of ion poloidal rotation theories have been performed on DIII-D using a novel impurity poloidal rotation diagnostic. These tests show significant disagreements with theoretical predictions in various conditions, including L-mode plasmas with internal transport barriers (ITB), H-mode plasmas, and QH-mode plasmas. The theories tested include standard neoclassical theory, turbulence driven Reynolds stress, and fast-ion friction on the thermal ions. Poloidal rotation is observed to spin up at the formation of an ITB and makes a significant contribution to the measurement of the $$\vec{E}$$ × $$\vec{B}$$ shear that forms the ITB. In ITB cases, neoclassical theory agrees quantitatively with the experimental measurements only in the steep gradient region. Significant quantitative disagreement with neoclassical predictions is seen in the cores of ITB, QH-, and H-mode plasmas, demonstrating that neoclassical theory is an incomplete description of poloidal rotation. The addition of turbulence driven Reynolds stress does not remedy this disagreement; linear stability calculations and Doppler backscattering measurements show that disagreement increases as turbulence levels decline. Furthermore, the effect of fast-ion friction, by itself, does not lead to improved agreement; in QH-mode plasmas, neoclassical predictions are closest to experimental results in plasmas with the largest fast ion friction. Finally, predictions from a new model that combines all three effects show somewhat better agreement in the H-mode case, but discrepancies well outside the experimental error bars remain.
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [3] ;  [4] ;  [4] ;  [2] ;  [2] ;  [2] ;  [5] ;  [6]
  1. Univ. of California San Diego, La Jolla, CA (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  4. Univ. of California, Los Angeles, CA (United States)
  5. College of William and Mary, Williamsburg, VA (United States)
  6. Oak Ridge Associated Univ., Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
FC02-04ER54698
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 21; Journal Issue: 7; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of California, San Diego, CA (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1354824

Chrystal, Colin, Burrell, Keith H., Grierson, Brian A., Staebler, Gary M., Solomon, Wayne M., Wang, W. X., Rhodes, Terry L., Schmitz, Lothar, Kinsey, Jon E., Lao, Lang L., deGrassie, John S., Mordijck, Saskia, and Meneghini, Orso. Testing neoclassical and turbulent effects on poloidal rotation in the core of DIII-D. United States: N. p., Web. doi:10.1063/1.4887296.
Chrystal, Colin, Burrell, Keith H., Grierson, Brian A., Staebler, Gary M., Solomon, Wayne M., Wang, W. X., Rhodes, Terry L., Schmitz, Lothar, Kinsey, Jon E., Lao, Lang L., deGrassie, John S., Mordijck, Saskia, & Meneghini, Orso. Testing neoclassical and turbulent effects on poloidal rotation in the core of DIII-D. United States. doi:10.1063/1.4887296.
Chrystal, Colin, Burrell, Keith H., Grierson, Brian A., Staebler, Gary M., Solomon, Wayne M., Wang, W. X., Rhodes, Terry L., Schmitz, Lothar, Kinsey, Jon E., Lao, Lang L., deGrassie, John S., Mordijck, Saskia, and Meneghini, Orso. 2014. "Testing neoclassical and turbulent effects on poloidal rotation in the core of DIII-D". United States. doi:10.1063/1.4887296. https://www.osti.gov/servlets/purl/1354824.
@article{osti_1354824,
title = {Testing neoclassical and turbulent effects on poloidal rotation in the core of DIII-D},
author = {Chrystal, Colin and Burrell, Keith H. and Grierson, Brian A. and Staebler, Gary M. and Solomon, Wayne M. and Wang, W. X. and Rhodes, Terry L. and Schmitz, Lothar and Kinsey, Jon E. and Lao, Lang L. and deGrassie, John S. and Mordijck, Saskia and Meneghini, Orso},
abstractNote = {Experimental tests of ion poloidal rotation theories have been performed on DIII-D using a novel impurity poloidal rotation diagnostic. These tests show significant disagreements with theoretical predictions in various conditions, including L-mode plasmas with internal transport barriers (ITB), H-mode plasmas, and QH-mode plasmas. The theories tested include standard neoclassical theory, turbulence driven Reynolds stress, and fast-ion friction on the thermal ions. Poloidal rotation is observed to spin up at the formation of an ITB and makes a significant contribution to the measurement of the $\vec{E}$ × $\vec{B}$ shear that forms the ITB. In ITB cases, neoclassical theory agrees quantitatively with the experimental measurements only in the steep gradient region. Significant quantitative disagreement with neoclassical predictions is seen in the cores of ITB, QH-, and H-mode plasmas, demonstrating that neoclassical theory is an incomplete description of poloidal rotation. The addition of turbulence driven Reynolds stress does not remedy this disagreement; linear stability calculations and Doppler backscattering measurements show that disagreement increases as turbulence levels decline. Furthermore, the effect of fast-ion friction, by itself, does not lead to improved agreement; in QH-mode plasmas, neoclassical predictions are closest to experimental results in plasmas with the largest fast ion friction. Finally, predictions from a new model that combines all three effects show somewhat better agreement in the H-mode case, but discrepancies well outside the experimental error bars remain.},
doi = {10.1063/1.4887296},
journal = {Physics of Plasmas},
number = 7,
volume = 21,
place = {United States},
year = {2014},
month = {7}
}