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Title: Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D

Abstract

Thomson scattering produces n{sub e} profiles from measurement of scattered laser beam intensity. Rayleigh scattering provides a first calibration of the relation n{sub e} ∝ I{sub TS}, which depends on many factors (e.g., laser alignment and power, optics, and measurement systems). On DIII-D, the n{sub e} calibration is adjusted against an absolute n{sub e} from the density-driven cutoff of the 48 channel 2nd harmonic X-mode electron cyclotron emission system. This method has been used to calibrate Thomson n{sub e} from the edge to near the core (r/a > 0.15). Application of core electron cyclotron heating improves the quality of cutoff and depth of its penetration into the core, and also changes underlying MHD activity, minimizing crashes which confound calibration. Less fueling is needed as “ECH pump-out” generates a plasma ready to take up gas. On removal of gyrotron power, cutoff penetrates into the core as channels fall successively and smoothly into cutoff.

Authors:
 [1]; ;  [2]; ; ;  [3]
  1. Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)
  2. Lawrence Livermore National Lab, Livermore, California 94500 (United States)
  3. General Atomics, San Diego, California 92122 (United States)
Publication Date:
OSTI Identifier:
22596550
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 11; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CALIBRATION; CYCLOTRONS; DENSITY; DEPTH; DOUBLET-3 DEVICE; ECR HEATING; ELECTRONS; EMISSION; LASERS; MAGNETOHYDRODYNAMICS; MICROWAVE AMPLIFIERS; OPTICS; PLASMA; RAYLEIGH SCATTERING; THOMSON SCATTERING

Citation Formats

Brookman, M. W., E-mail: brookmanmw@fusion.gat.com, Austin, M. E., McLean, A. G., Carlstrom, T. N., Hyatt, A. W., and Lohr, J. Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D. United States: N. p., 2016. Web. doi:10.1063/1.4959916.
Brookman, M. W., E-mail: brookmanmw@fusion.gat.com, Austin, M. E., McLean, A. G., Carlstrom, T. N., Hyatt, A. W., & Lohr, J. Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D. United States. doi:10.1063/1.4959916.
Brookman, M. W., E-mail: brookmanmw@fusion.gat.com, Austin, M. E., McLean, A. G., Carlstrom, T. N., Hyatt, A. W., and Lohr, J. Tue . "Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D". United States. doi:10.1063/1.4959916.
@article{osti_22596550,
title = {Improved cross-calibration of Thomson scattering and electron cyclotron emission with ECH on DIII-D},
author = {Brookman, M. W., E-mail: brookmanmw@fusion.gat.com and Austin, M. E. and McLean, A. G. and Carlstrom, T. N. and Hyatt, A. W. and Lohr, J.},
abstractNote = {Thomson scattering produces n{sub e} profiles from measurement of scattered laser beam intensity. Rayleigh scattering provides a first calibration of the relation n{sub e} ∝ I{sub TS}, which depends on many factors (e.g., laser alignment and power, optics, and measurement systems). On DIII-D, the n{sub e} calibration is adjusted against an absolute n{sub e} from the density-driven cutoff of the 48 channel 2nd harmonic X-mode electron cyclotron emission system. This method has been used to calibrate Thomson n{sub e} from the edge to near the core (r/a > 0.15). Application of core electron cyclotron heating improves the quality of cutoff and depth of its penetration into the core, and also changes underlying MHD activity, minimizing crashes which confound calibration. Less fueling is needed as “ECH pump-out” generates a plasma ready to take up gas. On removal of gyrotron power, cutoff penetrates into the core as channels fall successively and smoothly into cutoff.},
doi = {10.1063/1.4959916},
journal = {Review of Scientific Instruments},
number = 11,
volume = 87,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2016},
month = {Tue Nov 15 00:00:00 EST 2016}
}