Towards a Physics-Based L-H Transition Model

POSTER

Abstract

L-mode turbulence properties, collisionality, and ion transport fluxes across the separatrix are shown to determine the pre-transition ion poloidal and diamagnetic L-mode edge flow and the shear flow amplification triggering the L-H transition. L-mode ion thermal fluxes increase with density above the power threshold minimum, and are higher in hydrogen than in deuterium plasmas. The long-range toroidal ExB flow correlation at the L-H transition trigger time is observed to peak at intermediate plasma density around the L-H power threshold minimum, and is higher in D-plasmas in comparison to H-plasmas, indicating a possible link between trigger physics and power threshold. The turbulence-driven poloidal ion flow is found decisive for initial turbulence suppression, with a Reynolds stress gradient sufficiently large to account for the measured poloidal flow acceleration in the plateau collisionality.

Authors

  • Lothar Schmitz

    UCLA, University of California, Los Angeles

  • T.L. Rhodes

    UCLA

  • T. Neiser

    UCLA

  • L. Bardoczi

    UCLA

  • Frank Jenko

    University of California, Los Angeles, UCLA, Department of Physics and Astronomy, University of California - Los Angeles, Department of Physics and Astronomy, University of California, Los Angeles, USA, Univ of California - Los Angeles

  • Frank Jenko

    University of California, Los Angeles, UCLA, Department of Physics and Astronomy, University of California - Los Angeles, Department of Physics and Astronomy, University of California, Los Angeles, USA, Univ of California - Los Angeles

  • P. Gohil

    GA

  • C. Chrystal

    General Atomics, GA

  • B.A. Grierson

    PPPL

  • D. Eldon

    PPPL, PRINCETON U, Princeton University

  • Z. Yan

    U.W. Madison, U. Wisconsin-Madison, U WISCONSIN, U. Wisc.-Madison, U Wisc M, U Wisc-Madison

  • G.R. McKee

    U.W. Madison, U. Wisconsin-Madison, U WISCONSIN, UW Madison, University of Wisconsin-Madison, U.W.-Madison, U Wisc. M, U. Wisc.-Madison, U Wisc M, U Wisc-Madison, UW-MADISON, UWisc

  • J. Boedo

    University of California San Diego, UCSD