Sherwood 2015

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approvedtalk.pdf2015-04-08 10:24:15Heinke Frerichs

Three-dimensional edge plasma and neutral gas modeling with the EMC3-EIRENE code on the example of RMP application in tokamaks - status and development plans

Author: Heinke G Frerichs
Requested Type: Consider for Invited
Submitted: 2015-01-16 16:55:09

Co-authors: T. E. Evans, Y. Feng, D. Reiter, O. Schmitz

Contact Info:
University of Wisconsin - Madison, Department of E
1500 Engineering Drive
Madison, WI   53706
USA

Abstract Text:
The development of a reliable computational model for the plasma edge in non-axisymmetric configurations is essential for both the interpretation of present day magnetic confined fusion experiments and for guiding the design activities for future next step devices such as ITER and Wendelstein 7-X. Three-dimensional models are naturally more computationally challenging than their two-dimensional counterparts, but they are required for a detailed analysis of the impact of resonant magnetic perturbations (RMPs) in tokamaks and for intrinsically non-axisymmetric stellarator configurations. One such tool is the EMC3-EIRENE code, a coupled transport solver for the fluid edge plasma in self-consistent interaction with neutral gas. It is a flexible tool regarding the magnetic field configuration (it has been applied to single null, disconnected double null and snow-flake divertor configurations at tokamaks, as well as to classical, quasi-helical and quasi-isodynamic stellarator configurations), but it still lacks the physical sophistication of present two-dimensional transport codes.

We will present an overview on results from application of the model to scenarios with RMP fields at DIII-D and highlight the shortcomings of the model compared to the experiment. This assessment focuses in particular on the power balance and parallel heat transport as well as the particle balance in high density regimes. We show first steps on advancing the model regarding both aspects and concentrate on recent activities facing the challenge to access detached divertor configurations with this numerical tool. A generalization of the particle balance was implemented allowing for localized gas sources as well as volume recombination. Recent exploratory simulations exhibit numerically unstable behavior which may be attributed to the iterative simulation procedure itself. We present an analysis of this numerically unstable state and propose an adaptive relaxation method for its stabilization.

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March 16-18, 2015
The Courant Institute, New York University