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Title: Experimentally-based ExB drifts in the DIII-D divertor and SOL calculated from integration of Ohm's law using Thomson scattering measurements of T e and n e

Abstract

We calculated the 2D spatial distributions of cross field drift velocities from 2D Thomson scattering measurements of T e and n e in the divertor and SOL of DIII-D. In contrast with the method that has been used on DIII-D where the 2D distribution of plasma potential V plasma is obtained from measurements of the probe floating potential of reciprocating probes, the present method does not require insertion of a probe into the plasma and can therefore be used in high power discharges. Furthermore, the 2D spatial distribution of V plasma is calculated from Ohm’s Law for the parallel electric field E || along each flux tube, E || s || = -1.71dT e/ds || - T e/n edn e/ds ||, where the Thomson scattering values of T e and n e are used. To within a constant of integration, V plasma is obtained by integrating E || along the flux-tubes (field lines); the constant is obtained for each flux tube using the sheath drop at the target calculated from the characteristic of Langmuir probes built into the divertor tiles. The 2D distributions of E./01/2 = -dV4/ds./01/2, E452510/2 = -dV4/ds452510/2, v789 452510/2 = E./01/2/B and v789 ./01/2 = E452510/2/B aremore » then calculated as well as the particle drift flux densities Γ789 452510/2 = nv789 452510/2 and Γ789 ./01/2 = nv789 ./01/2 for electrons, fuel ions and impurity ions, using the appropriate values of particle density, n.« less

Authors:
 [1];  [1];  [2];  [3]
  1. University of Toronto Inst. for Aerospace Studies, Toronto, ON (Canada)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE); USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1474367
Alternate Identifier(s):
OSTI ID: 1375000
Report Number(s):
LLNL-JRNL-752151
Journal ID: ISSN 2352-1791; PII: S2352179116300679
Grant/Contract Number:  
FC02-04ER54698; AC52-07NA27344; AC04-94AL8500
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nuclear Materials and Energy
Additional Journal Information:
Journal Volume: 12; Journal ID: ISSN 2352-1791
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DIII-D; divertor; drifts; Thomson scattering

Citation Formats

Stangeby, Peter C., Elder, J. David, McLean, Adam G., and Watkins, Jonathan G. Experimentally-based ExB drifts in the DIII-D divertor and SOL calculated from integration of Ohm's law using Thomson scattering measurements of Te and ne. United States: N. p., 2017. Web. doi:10.1016/j.nme.2017.03.021.
Stangeby, Peter C., Elder, J. David, McLean, Adam G., & Watkins, Jonathan G. Experimentally-based ExB drifts in the DIII-D divertor and SOL calculated from integration of Ohm's law using Thomson scattering measurements of Te and ne. United States. doi:10.1016/j.nme.2017.03.021.
Stangeby, Peter C., Elder, J. David, McLean, Adam G., and Watkins, Jonathan G. Mon . "Experimentally-based ExB drifts in the DIII-D divertor and SOL calculated from integration of Ohm's law using Thomson scattering measurements of Te and ne". United States. doi:10.1016/j.nme.2017.03.021. https://www.osti.gov/servlets/purl/1474367.
@article{osti_1474367,
title = {Experimentally-based ExB drifts in the DIII-D divertor and SOL calculated from integration of Ohm's law using Thomson scattering measurements of Te and ne},
author = {Stangeby, Peter C. and Elder, J. David and McLean, Adam G. and Watkins, Jonathan G.},
abstractNote = {We calculated the 2D spatial distributions of cross field drift velocities from 2D Thomson scattering measurements of Te and ne in the divertor and SOL of DIII-D. In contrast with the method that has been used on DIII-D where the 2D distribution of plasma potential Vplasma is obtained from measurements of the probe floating potential of reciprocating probes, the present method does not require insertion of a probe into the plasma and can therefore be used in high power discharges. Furthermore, the 2D spatial distribution of Vplasma is calculated from Ohm’s Law for the parallel electric field E|| along each flux tube, E|| s|| = -1.71dTe/ds|| - Te/nedne/ds||, where the Thomson scattering values of Te and ne are used. To within a constant of integration, Vplasma is obtained by integrating E|| along the flux-tubes (field lines); the constant is obtained for each flux tube using the sheath drop at the target calculated from the characteristic of Langmuir probes built into the divertor tiles. The 2D distributions of E./01/2 = -dV4/ds./01/2, E452510/2 = -dV4/ds452510/2, v789 452510/2 = E./01/2/B and v789 ./01/2 = E452510/2/B are then calculated as well as the particle drift flux densities Γ789 452510/2 = nv789 452510/2 and Γ789 ./01/2 = nv789 ./01/2 for electrons, fuel ions and impurity ions, using the appropriate values of particle density, n.},
doi = {10.1016/j.nme.2017.03.021},
journal = {Nuclear Materials and Energy},
number = ,
volume = 12,
place = {United States},
year = {Mon Mar 27 00:00:00 EDT 2017},
month = {Mon Mar 27 00:00:00 EDT 2017}
}

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