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Progress on Validation of Extended MHD models by the Plasma Science and Innovation Center

Author: Cihan Akcay
Requested Type: Consider for Invited
Submitted: 2012-12-07 15:25:43

Co-authors: A. Glasser, C. Hansen, E.D. Held, T.R. Jarboe, J.-Y. Ji, C. Kim, W. Lowrie, V.S. Lukin, G. Marklin, E. Meier, R. Milroy, J.B. O’Bryan, B.A. Nelson, C. R. Sovinec, and U. Shumlak

Contact Info:
University of Washigton
Aerospace and energetics resea
Seattle, WA   98195
US

Abstract Text:
C. Akcay, A. Glasser, C. Hansen, T.R. Jarboe, G. Marklin, R. Milroy, B.A. Nelson, and U. Shumlak
University of Washington

J. B. O'Bryan and C. R. Sovinec
University of Wisconsin

E. Held and J. Y. Ji
Utah State University

E. T. Meier
Lawrence Livermore National Laboratory

V. S. Lukin
Naval Research Laboratory

C. C. Kim
FarTech Inc.

W. Lowrie
Applied Research Associates Inc.


We present results on validation efforts by the Plasma Science and Innovation Center (PSI-Center) in collaboration with the following validation platform experiments: the Helicity Injected Torus (HIT-SI), Translation Confinement Sustainment Upgrade (TCSU), and Zap flow Z-pinch.
The computational highlights by the PSI-Center include adding reacting neutrals in the MHD model, incorporating energetic particles in extended MHD modeling, multi-block grid generation imported from a CAD description, and simulating 3D physics of rotating magnetic field (RMF) and inductive asymmetric current drive with two-fluid MHD (2fl-MHD).
The PSI center collaborates with various magnetic confinement experiments to refine the codes with the goal of improving computational predictability while providing computational support for the experiments.
Thus, it serves as a general validation platform for both the codes and eventually the experiments.
The center works primarily on the development and application of NIMROD and HiFi MHD codes.
NIMROD uses 2D finite elements (FE) in the poloidal plane and Fourier expansion in the periodic direction for spatial discretization with semi-implicit time stepping.
HiFi uses a 3D-FE spatial discretization with a multi-block grid and implicit time stepping.
HIT-SI bow tie spheromak uses two geometrically asymmetric injectors to inductively inject magnetic helicity for current drive.
Hall MHD NIMROD simulations show generation of a significant toroidally symmetric plasma current Itor similar to the experiment.
Synthetic diagnostics from the simulation show good agreement with time-averaged internal magnetic profiles and eigenmode structure of the surface magnetic fields.
The TCSU field reversed configuration (FRC) investigates RMF current drive to generate and sustain an FRC. Three-dimensional
Hall-MHD NIMROD simulations using experimental parameters show the generation of an FRC with toroidal magnetic field and size that compare well with experimental results.
The ZaP Flow Z-pinch experiment investigates the effect of wall stabilization for a partial conducting wall.
HiFi simulations of a Z-pinch with a cylindrical conducting wall are compared to a case with extrusions that represent perforations in the experimental wall.
Pinches of various radii are simulated.
Both experimental data and simulations indicate that the conducting wall has no discernible effect on stability in the ZaP experiment.

Characterization: 2.0

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