Study of high field side/low field side asymmetry in the electron temperature profile with electron cyclotron emission
POSTER
Abstract
Electron cyclotron emission (ECE) provides high resolution measurements of electron temperature profiles ($T_{\mathrm{e}}(R,t))$ in tokamaks. Calibration accuracy of this data can be improved using a sawtooth averaging technique. This improved calibration will then be utilized to determine the symmetry of $T_{\mathrm{e\thinspace }}$profiles by comparing low field side (LFS) and high field side (HFS) measurements. Although $T_{\mathrm{e}}$ is considered constant on flux surfaces, cases have been observed in which there are pronounced asymmetries about the magnetic axis, particularly with increased pressure. Trends in LFS/HFS overlap are examined as functions of plasma pressure, MHD mode presence, heating techniques, and other discharge conditions. This research will provide information on the accuracy of the current two-dimensional mapping of flux surfaces in the tokamak. Findings can be used to generate higher quality EFITs and inform ECE calibration.
Authors
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V.R. Gugliada
Ithaca Coll
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M.E. Austin
IFS, Univ. of Texas, Austin, U. Texas, University of Texas at Austin, UA Texas
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M.W. Brookman
U. Texas, University of Texas at Austin, Institute for Fusion Studies, University of Texas