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Title: Boundary displacement measurements using multi-energy soft x-rays

The Multi-Energy Soft X-ray (ME-SXR) system on NSTX provides radial profiles of soft X-ray emission, measured through a set of filters with varying thickness, which have been used to reconstruct the electron temperature on fast time scales (∼10 kHz). In addition to this functionality, here we show that the ME-SXR system can be used to measure the boundary displacement of the NSTX plasma with a few mm spatial resolution during magnetohydrodyamic (MHD) activity. Boundary displacement measurements can serve to inform theoretical predictions of neoclassical toroidal viscosity, and will be used to investigate other edge phenomena on NSTX-U. For example, boundary measurements using filtered SXR measurements can provide information on pedestal steepness and dynamic evolution leading up to and during edge localized modes (ELMs). Future applications include an assessment of a simplified, filtered SXR edge detection system as well as its suitability for real-time non-magnetic boundary feedback for ELMs, MHD, and equilibrium position control.
Authors:
;  [1] ; ;  [2] ;  [3]
  1. Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States)
  2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)
  3. Department of Applied Physics and Mathematics, Columbia University, New York City, New York 10027 (United States)
Publication Date:
OSTI Identifier:
22303474
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; CONTROL; DETECTION; EDGE LOCALIZED MODES; ELECTRON TEMPERATURE; FILTERS; KHZ RANGE; MAGNETOHYDRODYNAMICS; NSTX DEVICE; PLASMA; SOFT X RADIATION; SPATIAL RESOLUTION; VISCOSITY