Reversed Shear Alfv\'{e}n Eigenmode Stabilization by Localized Electron Cyclotron Heating

POSTER

Abstract

Reversed shear Alfv\'{e}n eigenmode (RSAE) activity in DIII-D is observed to be stabilized by electron cyclotron heating (ECH) near the minimum of the safety factor (q$_{min})$ in neutral beam heated discharges with reversed magnetic shear. The degree of RSAE stabilization and the volume averaged neutron production (S$_{n})$ are highly dependent on ECH deposition location relative to q$_{min}$. Ideal MHD simulations predict RSAE existence during ECH, indicating that the mode disappearance is due to kinetic effects not taken into account by the ideal MHD model. While discharges with ECH stabilization of RSAEs have higher S$_{n}$ than discharges with significant RSAE activity, neutron production remains strongly reduced (up to 60{\%}), indicating the bulk of the deficit is not due to RSAEs alone.

*Supported by the US DOE under DE-FC02-04ER54698, SC-G903402, DE-AC02-76CH03073, DE-FG03-97ER54415, DE-FG02-01ER54615, W-7405-ENG-48, and DE-FG02-89ER53296.

Authors

  • M.A. Van Zeeland

    • GA
    • General Atomics

  • P.S. Johnson

    • General Atomics
    • Butler U.

  • W.W. Heidbrink

    • UC-Irvine
    • University of California, Irvine
    • UCI

  • R. Nazikian

    • PPPL
    • Princeton Plasma Physics Laboratory

  • W.M. Solomon

    • PPPL

  • N.N. Gorelenkov

    • PPPL

  • G.J. Kramer

    • PPPL

  • M.E. Austin

    • U. Texas-Austin
    • U. Texas

  • T.L. Rhodes

    • UCLA

  • C. Holcomb

    • Lawrence Livermore National Laboratory
    • LLNL

  • M.A. Makowski

    • Lawrence Livermore National Laboratory
    • LLNL

  • G.R. McKee

    • University of Wisconsin-Madison
    • U. Wisc.-Madison
    • U. Wisc.
    • U. Wisconsin
    • U. Wisc-Madison

  • S.E. Sharapov

    • UKAEA