Isotope dependence of the radial electric field in the DIII-D tokamak

POSTER

Abstract

DIII-D experiments in hydrogen and deuterium plasmas have identified differences in the L-mode radial electric field profiles between isotopes just before the L-H transition, which are observed by four independent radial electric field diagnostics: impurity charge exchange spectroscopy, Doppler BackScattering, Beam Emission Spectroscopy, and Langmuir probes. The electric field differences between isotope plasmas are investigated from the perspective of both the open and closed field line regions. In the open field line region, a hotter outer strike point is found to generate a more positive radial electric field at the separatrix in hydrogen plasmas compared to deuterium. In the closed field line region, the higher radial electric field is attributed to changes in poloidal rotation and turbulent Reynolds stress between isotopes, with Reynolds stress profiles consistent with predictions from E×B shear eddy tilting. The measured differences in L-mode Er and E×B shear are modeled to quantitatively assess their impact on the observed L-H transition power threshold.

*Acknowledgements: This work was supported by the US Department of Energy under Awards No. DE-FC02-04ER54698, DE-SC0020287, DE-SC0019352, DE-FG02-95ER54309, DE-SC0024399, DE-AC02-09CH11466, DE-AC05-00OR22725, DE-AC52-07NA27344, DE-FG02-08ER5499 and DE-SC0014264.

Presenters

  • Kyle Callahan

    • University of California, Los Angeles

Authors

  • Kyle Callahan

    • University of California, Los Angeles

  • Lothar W Schmitz

    • University of California Los Angeles, TAE Technologies
    • University of California, Los Angeles
    • University of California Los Angeles

  • Troy A Carter

    • University of California, Los Angeles

  • Quinn Pratt

    • University of California, Los Angeles

  • Kathreen E Thome

    • General Atomics - San Diego
    • General Atomics

  • Emily A Belli

    • General Atomics

  • Shaun R Haskey

    • Princeton Plasma Physics Laboratory

  • Adrianna Angulo

    • Princeton Plasma Physics Laboratory

  • Colin Chrystal

    • General Atomics - San Diego
    • General Atomics

  • Arash Ashourvan

    • General Atomics

  • Tom F Neiser

    • General Atomics - San Diego

  • Brian A Grierson

    • General Atomics

  • Filipp O Khabanov

    • University of Wisconsin - Madison
    • Univ Wisconsin,Madison

  • George R McKee

    • University of Wisconsin-Madison
    • University of Wisconsin, Madison

  • Zheng Yan

    • University of Wisconsin - Madison
    • University of Wisconsin Madison

  • Christopher G Holland

    • University of California, San Diego

  • Alessandro Bortolon

    • Princeton Plasma Physics Laboratory

  • Matthias Knolker

    • General Atomics

  • Filippo Scotti

    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Laboratory

  • Andreas Michael Holm

    • Lawrence Livermore Natl Lab
    • Lawrence Livermore National Laboratory

  • Dinh Truong

    • Sandia National Laboratory, Livermore, CA
    • Lawrence Livermore National Laboratory

  • Robert S Wilcox

    • Oak Ridge National Laboratory

  • Gary M Staebler

    • Oak Ridge National Laboratory

  • Raul Gerru Miguelanez

    • MIT