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.

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