Effects of medium-Z impurity on H-mode pedestal in DIII-D

POSTER

Abstract

The effects of neon level on H-mode pedestal structure at two heating powers in DIII-D lower-single-null discharges are studied. In 3 MW discharges, neon injection resulted in an increase in plasma stored energy and confinement of 30% and 25% respectively. After neon injection, the ELM frequency dropped, the electron pedestal density and pressure increased, and the pedestal temperature slowly decreased. In 6 MW discharges, at the same and even larger neon level, the plasma confinement increased slightly and stored energy gradually increased by up to 15%, while the trend of ELM and pedestal changes was similar to 3 MW discharges. In the neon enhanced confinement phases, the critical pressure gradient along the ballooning boundary of Peeling-Ballooning mode increased. The observed pedestal width will be compared with that predicted by EPED1.0. STRAHL simulations of impurity transport will discussed, as well as the relation between fluctuations and the observed transport changes.

Presenters

  • Heng Lan

    Institute of Plasma Physics, Chinese Academy of Sciences, University of Chinese Academy of Sciences

Authors

  • Heng Lan

    Institute of Plasma Physics, Chinese Academy of Sciences, University of Chinese Academy of Sciences

  • Tom H Osborne

    General Atomics, General Atomics - San Diego

  • B.A. A Grierson

    PPPL, Princeton Plasma Phys Lab, Princeton Plasma Physics Laboratory

  • B.S. S Victor

    Lawrence Livermore National Laboratory, LLNL

  • Richard Joseph Groebner

    General Atomics - San Diego, General Atomics

  • Kshitish Barada

    University of California, Los Angeles, University of California Los Angeles

  • Terry L Rhodes

    Univ of California - Los Angeles, University of California, Los Angeles, UCLA, University of California Los Angeles

  • George R Mckee

    Univ of Wisconsin, Madison, Univ of Wisconsin, Madison, Univ of Wisconsin, Madison, University of Wisconsin–Madison, University of Wisconsin-Madison, University of Wisconsin - Madison, University of Wisconsin, Madison, Univ. of Wisconsin, Madison

  • Anthony W Leonard

    General Atomics - San Diego, General Atomics, USA, General Atomics

  • Huiqian Wang

    Oak Ridge Associated Universities, General Atomics - San Diego, Oak Ridge Associated University, ORAU, Oak Ridge, TN, USA, Oak Ridge Associated Universities, USA, Oak Ridge Associated Universities, USA, General Atomics

  • Guosheng Xu

    Institute of Plasma Physics, Chinese Academy of Sciences, ASIPP