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Title: Use of reconstructed 3D VMEC equilibria to match effects of toroidally rotating discharges in DIII-D

Abstract

Here, a technique for tokamak equilibrium reconstructions is used for multiple DIII-D discharges, including L-mode and H-mode cases when weakly 3D fields $$\left(\delta B/B\sim {{10}^{-3}}\right)$$ are applied. The technique couples diagnostics to the non-linear, ideal MHD equilibrium solver VMEC, using the V3FIT code, to find the most likely 3D equilibrium based on a suite of measurements. It is demonstrated that V3FIT can be used to find non-linear 3D equilibria that are consistent with experimental measurements of the plasma response to very weak 3D perturbations, as well as with 2D profile measurements. Observations at DIII-D show that plasma rotation larger than 20 krad s –1 changes the relative phase between the applied 3D fields and the measured plasma response. Discharges with low averaged rotation (10 krad s –1) and peaked rotation profiles (40 krad s –1) are reconstructed. Similarities and differences to forward modeled VMEC equilibria, which do not include rotational effects, are shown. Toroidal phase shifts of up to $${{30}^{\circ}}$$ are found between the measured and forward modeled plasma responses at the highest values of rotation. The plasma response phases of reconstructed equilibra on the other hand match the measured ones. This is the first time V3FIT has been used to reconstruct weakly 3D tokamak equilibria.

Authors:
 [1];  [1];  [1];  [1];  [1];  [2];  [1];  [3];  [4];  [3];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Columbia Univ., New York, NY (United States)
  3. General Atomics, San Diego, CA (United States)
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program. ORNL Director's R&D; USDOE Office of Science (SC)
Contributing Org.:
Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA Columbia University, New York, New York, USA Princeton Plasma Physics Laboratory, Princeton, New Jersey, USA
OSTI Identifier:
1331096
Alternate Identifier(s):
OSTI ID: 1329078; OSTI ID: 1335700; OSTI ID: 1372069
Grant/Contract Number:  
AC05-00OR22725; FG02-04ER54761; FC02-04ER54698; AC02-09CH11466
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 1; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; VMEC; DIII-D; equilibrium reconstruction; plasma response

Citation Formats

Wingen, Andreas, Wilcox, Robert S., Cianciosa, Mark R., Seal, Sudip K., Unterberg, Ezekial A., Hanson, Jeremy M., Hirshman, Steven Paul, Lao, L. L., Logan, N. C., Paz-Soldan, Carlos, and Shafer, Morgan W. Use of reconstructed 3D VMEC equilibria to match effects of toroidally rotating discharges in DIII-D. United States: N. p., 2016. Web. doi:10.1088/0029-5515/57/1/016013.
Wingen, Andreas, Wilcox, Robert S., Cianciosa, Mark R., Seal, Sudip K., Unterberg, Ezekial A., Hanson, Jeremy M., Hirshman, Steven Paul, Lao, L. L., Logan, N. C., Paz-Soldan, Carlos, & Shafer, Morgan W. Use of reconstructed 3D VMEC equilibria to match effects of toroidally rotating discharges in DIII-D. United States. doi:10.1088/0029-5515/57/1/016013.
Wingen, Andreas, Wilcox, Robert S., Cianciosa, Mark R., Seal, Sudip K., Unterberg, Ezekial A., Hanson, Jeremy M., Hirshman, Steven Paul, Lao, L. L., Logan, N. C., Paz-Soldan, Carlos, and Shafer, Morgan W. Thu . "Use of reconstructed 3D VMEC equilibria to match effects of toroidally rotating discharges in DIII-D". United States. doi:10.1088/0029-5515/57/1/016013. https://www.osti.gov/servlets/purl/1331096.
@article{osti_1331096,
title = {Use of reconstructed 3D VMEC equilibria to match effects of toroidally rotating discharges in DIII-D},
author = {Wingen, Andreas and Wilcox, Robert S. and Cianciosa, Mark R. and Seal, Sudip K. and Unterberg, Ezekial A. and Hanson, Jeremy M. and Hirshman, Steven Paul and Lao, L. L. and Logan, N. C. and Paz-Soldan, Carlos and Shafer, Morgan W.},
abstractNote = {Here, a technique for tokamak equilibrium reconstructions is used for multiple DIII-D discharges, including L-mode and H-mode cases when weakly 3D fields $\left(\delta B/B\sim {{10}^{-3}}\right)$ are applied. The technique couples diagnostics to the non-linear, ideal MHD equilibrium solver VMEC, using the V3FIT code, to find the most likely 3D equilibrium based on a suite of measurements. It is demonstrated that V3FIT can be used to find non-linear 3D equilibria that are consistent with experimental measurements of the plasma response to very weak 3D perturbations, as well as with 2D profile measurements. Observations at DIII-D show that plasma rotation larger than 20 krad s–1 changes the relative phase between the applied 3D fields and the measured plasma response. Discharges with low averaged rotation (10 krad s–1) and peaked rotation profiles (40 krad s–1) are reconstructed. Similarities and differences to forward modeled VMEC equilibria, which do not include rotational effects, are shown. Toroidal phase shifts of up to ${{30}^{\circ}}$ are found between the measured and forward modeled plasma responses at the highest values of rotation. The plasma response phases of reconstructed equilibra on the other hand match the measured ones. This is the first time V3FIT has been used to reconstruct weakly 3D tokamak equilibria.},
doi = {10.1088/0029-5515/57/1/016013},
journal = {Nuclear Fusion},
issn = {0029-5515},
number = 1,
volume = 57,
place = {United States},
year = {2016},
month = {10}
}

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