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3D Equilibrium Reconstruction on Madison Symmetric Torus

Author: Jonathan J. Koliner
Requested Type: Poster Only
Submitted: 2014-05-30 17:38:32

Co-authors: B. E. Chapman, M. R. Cianciosa, J. D. Hanson, S. Munaretto, W. Capecchi, J. K. Anderson, J. S. Sarff

Contact Info:
UW-Madison
1150 University Avenue
Madison, WI   53706
USA

Abstract Text:
Plasmas in the MST reversed field pinch (RFP) bifurcate to a helical equilibrium, forming a Single Helical Axis (SHAx) at high plasma current (Ip≈500 kA) and low density (ne≈0.5 x 1019 m-3). Fast ion confinement time is decreased while energy confinement time is increased compared to the multi-helicity (MH) traditional RFP. In order to model plasma parameters in 3D equilibria, the V3FIT equilibrium reconstruction code is applied with diagnostic measurements as constraints. The 11-chord interferometer-polarimeter, 22-point Thomson scattering system, and 4-camera soft X-ray probes have been included in addition to external magnetics. Equilibria have been generated for several time points per shot using a fixed plasma boundary with no external currents. Model signals fit well to observed signals, including Faraday rotation, χ2 ≈ 1. A filament current model has been created to simulate the conducting shell with many external currents for a free plasma boundary solution. Axisymmetric equilibria have been reconstructed using the filament model and compared to solutions obtained with the MSTFIT axisymmetric equilibrium reconstruction code. The filament model has been extended to allow reconstruction of helical equilibria. The generated VMEC equilibrium serves as the input for applications relevant to the study of plasma parameters.

Characterization: 4.0

Comments:
Place with MST group.

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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