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Electron temperature and density turbulence behavior during sawtooth oscillations in DIII-D

POSTER

Abstract

The sawtooth instabilities in tokamaks are periodic magnetic reconnection events, where the plasma pressure profiles inside a certain plasma minor radius (the inversion radius) drop abruptly. This work reports on recent observations of the electron temperature (Te) and density (Ne) turbulence behavior during sawtooth oscillations in a DIII-D hydrogen L-mode plasma with an inner wall limited configuration, measured by the correlation electron-cyclotron-emission (CECE) radiometer and Doppler backscattering (DBS) systems. It is observed that both Te and Ne turbulence amplitudes vary with time during sawtooth cycles. Before each sawtooth crash, the Te and Ne turbulence amplitudes reach a maximum level, then they show clear decrease immediately after sawtooth crash well inside the inversion radius, while no obvious change occurs near and outside the inversion radius. A critical Te gradient behavior is found inside the inversion radius but not near or outside the inversion radius. Evidence of radial propagation of Te turbulence is observed at the sawtooth crash. These observations combined with data from magnetic probes and linear stability turbulence simulations will be presented.

Presenters

  • Guiding Wang

    University of California, Los Angeles

Authors

  • Guiding Wang

    University of California, Los Angeles

  • Terry L Rhodes

    University of California, Los Angeles, UCLA

  • William A Peebles

    University of California, Los Angeles

  • Neal A Crocker

    University of California, Los Angeles

  • Rongjie Hong

    UCLA, University of California, Los Angeles

  • Quinn Pratt

    University of California, Los Angeles

  • Max E Austin

    University of Texas at Austin, University of Texas Austin

  • Michael Van Zeeland

    General Atomics - San Diego, General Atomics

  • Sterling P Smith

    General Atomics, General Atomics - San Diego