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

Journal Article · Mon Mar 27 00:00:00 EDT 2017 · Nuclear Materials and Energy

DOI:https://doi.org/10.1016/j.nme.2017.03.021· OSTI ID:1474367

Stangeby, Peter C. ^[1]; Elder, J. D. ^[1]; McLean, A. G. ^[2]; Watkins, J. G. ^[3]

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1. Univ. of Toronto, Toronto, ON (Canada)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

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 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.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: AC52-07NA27344; FC02-04ER54698; AC04-94AL8500
• OSTI ID: 1474367
• Alternate ID(s): OSTI ID: 1375000
• Report Number(s): LLNL-JRNL-752151; 931424
• Journal Information: Nuclear Materials and Energy, Vol. 12, Issue C; ISSN 2352-1791
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DIII-D
divertor
drifts
Thomson scattering