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Measurements of CECE/nT-phase spot size at ASDEX Upgrade

POSTER

Abstract

Turbulence is known to be responsible for anomalous transport in tokamaks, reducing energy confinement times and limiting reactor performance. The correlation electron cyclotron emission (CECE) and ne-Te cross-phase diagnostics installed on the ASDEX Upgrade (AUG) tokamak measure broadband, long wavelength (kθρs approximately <0.3) electron temperature and density fluctuations, yielding insight into turbulence-driven transport. The poloidal spot size, determined by focusing optics, is critical in determining the physical dimensions of the turbulence measured, with a smaller value of spot size yielding higher poloidal resolution in the measurement. To measure the spot size of the combined CECE/ ne-Te cross-phase diagnostic in use at AUG, an identical optical set up is constructed and tested at MIT. Here we present the details of the optical set up as well as the results of the tests to determine the spot size of these diagnostics. These measurements will enable a more accurate analysis of CECE and ne-Te cross-phase data and improve our understanding of turbulent fluctuations.

Presenters

  • Calvin Cummings

    Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MI

Authors

  • Calvin Cummings

    Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MI

  • Rachel Bielajew

    Massachusetts Institute of Technology MIT, Cambride, USA, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MI

  • William Burke

    Massachusetts Institute of Technology MIT, MIT, MIT PSFC

  • Garrard D Conway

    Max-Planck-Institut für Plasmaphysik, Garching, Germany, Max Planck Institute for Plasma Physics, Garching, Germany, Max Planck Institute for Plasma Physics

  • Pedro A Molina Cabrera

    Max-Planck-Institut für Plasmaphysik, Garching, Germany, Max Planck Institute for Plasma Physics, Massachusetts Institute of Technology MIT

  • Pablo Rodriguez-Fernandez

    Massachusetts Institute of Technology MI, MIT PSFC, Massachusetts Institute of Technology MIT, MIT, Massachusetts Institute of Technology, MIT Plasma Science and Fusion Center, Cambridge, MA02139, USA

  • Christian Yoo

    Massachusetts Institute of Technology MIT

  • Anne E White

    Massachusetts Institute of Technology MIT, Cambride, USA, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MI, MIT PSFC