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galante_epr_pub.pdf2014-08-20 08:17:04Matthew Galante
galante_epr_2014_submit-1.pdf2014-05-29 14:32:35Matthew Galante
galante_epr_2014_submit.pdf2014-05-28 15:54:49Matthew Galante

Determination of Zeff in the Madison Symmetric Torus through Integrated Data Analysis

Author: Matthew E. Galante
Requested Type: Consider for Invited
Submitted: 2014-05-29 14:32:14

Co-authors: L.M. Reusch, D.J. Den Hartog, P. Franz, J.R. Johnson, M.B. McGarry, H.D. Stephens

Contact Info:
University of Wisconsin-Madison
1150 University Ave
Madison , WI   53706
United States

Abstract Text:
On most plasma science experiments, a maximum of knowledge must be gleaned from limited data sets. Integrated data analysis (IDA) enables combination of measurements and uncertainties from multiple, distinct diagnostics in a statistical framework to determine the single most probable result for a physical parameter of interest. Conventionally, a parameter of interest is measured by individual diagnostics and the differing measurements compared for agreement. IDA differs in that all available data is combined and the parameter of interest, along with its uncertainty, is found. The method is highly modular, allowing for easy inclusion of many independent diagnostics. IDA has already been applied to a number of plasma experiments to determine quantities of interest such as electron temperature and density. Using data from several diagnostics on the Madison Symmetric Torus (MST), a framework is being developed to determine the effective ionic charge (Zeff). This parameter cannot be accurately determined by any single diagnostic on MST, but is of key importance to the growing MHD validation effort. Initial results from MST indicate that Zeff, as determined from soft x-ray tomography coupled with charge exchange recombination spectroscopy (CHERS) measurements for carbon and aluminum, is approximately 2 in the core of high current, high temperature discharges and has a hollow profile, peaking near mid-radius. In addition to determination of Zeff, the IDA framework is being applied to other parameters on MST (e.g., temperature and density). Specifically, work has begun to couple Thomson scattering and soft x-ray tomography measurements to produce an electron temperature profile that is more precise than either measurement individually. The IDA framework developed for MST should be applicable to other experiments, and may be particularly important on burning plasma experiments where data and measurements are likely to be sparse.
This work supported by US DOE.

Characterization: 2.0


Workshop on Exploratory Topics in Plasma and Fusion Research (EPR) and US-Japan Compact Torus (CT) Workshop
August 5-8, 2014
Madison, Wisconsin

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