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Title: Linearized spectrum correlation analysis for line emission measurements

Abstract

A new spectral analysis method, Linearized Spectrum Correlation Analysis (LSCA), for charge exchange and passive ion Doppler spectroscopy is introduced to provide a means of measuring fast spectral line shape changes associated with ion-scale micro-instabilities. This analysis method is designed to resolve the fluctuations in the emission line shape from a stationary ion-scale wave. The method linearizes the fluctuations around a time-averaged line shape (e.g., Gaussian) and subdivides the spectral output channels into two sets to reduce contributions from uncorrelated fluctuations without averaging over the fast time dynamics. In principle, small fluctuations in the parameters used for a line shape model can be measured by evaluating the cross spectrum between different channel groupings to isolate a particular fluctuating quantity. High-frequency ion velocity measurements (100–200 kHz) were made by using this method. We also conducted simulations to compare LSCA with a moment analysis technique under a low photon count condition. Both experimental and synthetic measurements demonstrate the effectiveness of LSCA.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1];  [1]
  1. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Research Org.:
Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1535339
Grant/Contract Number:  
FC02-05ER54814
Resource Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 88; Journal Issue: 8; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; Instruments & Instrumentation; Physics

Citation Formats

Nishizawa, T., Nornberg, M. D., Den Hartog, D. J., and Sarff, J. S. Linearized spectrum correlation analysis for line emission measurements. United States: N. p., 2017. Web. doi:10.1063/1.4999450.
Nishizawa, T., Nornberg, M. D., Den Hartog, D. J., & Sarff, J. S. Linearized spectrum correlation analysis for line emission measurements. United States. doi:10.1063/1.4999450.
Nishizawa, T., Nornberg, M. D., Den Hartog, D. J., and Sarff, J. S. Tue . "Linearized spectrum correlation analysis for line emission measurements". United States. doi:10.1063/1.4999450. https://www.osti.gov/servlets/purl/1535339.
@article{osti_1535339,
title = {Linearized spectrum correlation analysis for line emission measurements},
author = {Nishizawa, T. and Nornberg, M. D. and Den Hartog, D. J. and Sarff, J. S.},
abstractNote = {A new spectral analysis method, Linearized Spectrum Correlation Analysis (LSCA), for charge exchange and passive ion Doppler spectroscopy is introduced to provide a means of measuring fast spectral line shape changes associated with ion-scale micro-instabilities. This analysis method is designed to resolve the fluctuations in the emission line shape from a stationary ion-scale wave. The method linearizes the fluctuations around a time-averaged line shape (e.g., Gaussian) and subdivides the spectral output channels into two sets to reduce contributions from uncorrelated fluctuations without averaging over the fast time dynamics. In principle, small fluctuations in the parameters used for a line shape model can be measured by evaluating the cross spectrum between different channel groupings to isolate a particular fluctuating quantity. High-frequency ion velocity measurements (100–200 kHz) were made by using this method. We also conducted simulations to compare LSCA with a moment analysis technique under a low photon count condition. Both experimental and synthetic measurements demonstrate the effectiveness of LSCA.},
doi = {10.1063/1.4999450},
journal = {Review of Scientific Instruments},
number = 8,
volume = 88,
place = {United States},
year = {2017},
month = {8}
}

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