# Center for Extended Magnetohydrodynamic Modeling (CEMM, UW-Madison Physics)

## Abstract

The Center for Extended Magnetohydrodynamic Modeling (CEMM) focused on the further development, verification, validation, and application of two scientific computation programs, the NIMROD and M3D-C1 codes, for modeling macroscopic dynamics in magnetized plasma. Both NIMROD and M3D-C1 solve the mathematical equations that model two-fluid 3D magnetohydrodynamic (MHD). They are designed and optimized to be efficient and accurate for toroidal confinement physics calculations. The effort improved the fidelity of the physics models, the realism of the treatment of the surrounding vessel, coils, and other structures, the accuracy and efficiency of the algorithms, and the ability to scale calculations to thousands of processors in order to take advantage of leading-edge computers. The primary application areas of Resonant Magnetic Perturbations (RMP), Edge Harmonic Oscillations (EHO), Edge Localized Modes (ELMs), Disruption Studies, Sawteeth and Stationary States, and Kinetic MHD and Neoclassical Tearing Modes (NTM) are of concern for the international ITER experiment, which is under construction in France. The component of CEMM that is described in this report applied recently developed aspects of NIMROD to sawtooth and EHO dynamics, which occur in tokamak plasma confinement systems. In particular, the effort researched energetic-particle, two-fluid, and plasma-flow effects. The work included an effort to validate energetic-particlemore »

- Authors:

- Univ. of Wisconsin-Madison, Madison, WI (United States)

- Publication Date:

- Research Org.:
- Univ. of Wisconsin-Madison, Madison, WI (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)

- OSTI Identifier:
- 1438177

- Report Number(s):
- DOE/ER-54974

- DOE Contract Number:
- FC02-08ER54974

- Resource Type:
- Technical Report

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma computation; magnetohydrodynamic stability

### Citation Formats

```
Sovinec, C. R.
```*Center for Extended Magnetohydrodynamic Modeling (CEMM, UW-Madison Physics)*. United States: N. p., 2018.
Web. doi:10.2172/1438177.

```
Sovinec, C. R.
```*Center for Extended Magnetohydrodynamic Modeling (CEMM, UW-Madison Physics)*. United States. doi:10.2172/1438177.

```
Sovinec, C. R. Fri .
"Center for Extended Magnetohydrodynamic Modeling (CEMM, UW-Madison Physics)". United States. doi:10.2172/1438177. https://www.osti.gov/servlets/purl/1438177.
```

```
@article{osti_1438177,
```

title = {Center for Extended Magnetohydrodynamic Modeling (CEMM, UW-Madison Physics)},

author = {Sovinec, C. R.},

abstractNote = {The Center for Extended Magnetohydrodynamic Modeling (CEMM) focused on the further development, verification, validation, and application of two scientific computation programs, the NIMROD and M3D-C1 codes, for modeling macroscopic dynamics in magnetized plasma. Both NIMROD and M3D-C1 solve the mathematical equations that model two-fluid 3D magnetohydrodynamic (MHD). They are designed and optimized to be efficient and accurate for toroidal confinement physics calculations. The effort improved the fidelity of the physics models, the realism of the treatment of the surrounding vessel, coils, and other structures, the accuracy and efficiency of the algorithms, and the ability to scale calculations to thousands of processors in order to take advantage of leading-edge computers. The primary application areas of Resonant Magnetic Perturbations (RMP), Edge Harmonic Oscillations (EHO), Edge Localized Modes (ELMs), Disruption Studies, Sawteeth and Stationary States, and Kinetic MHD and Neoclassical Tearing Modes (NTM) are of concern for the international ITER experiment, which is under construction in France. The component of CEMM that is described in this report applied recently developed aspects of NIMROD to sawtooth and EHO dynamics, which occur in tokamak plasma confinement systems. In particular, the effort researched energetic-particle, two-fluid, and plasma-flow effects. The work included an effort to validate energetic-particle modeling using laboratory measurements and previous analysis of giant sawtooth oscillations, where energetic particles temporarily stabilize the system. A side effort that grew out of this work was benchmarking of the slab-geometry ion temperature gradient (ITG) instability computed by NIMROD's two-fluid modeling against analytical results. These fluid-model results were also compared with results from kinetic modeling to help quantify the range of validity for the two-fluid model. The EHO simulations show that sheared plasma flow plays a crucial role in saturating the underlying MHD instability.},

doi = {10.2172/1438177},

journal = {},

number = ,

volume = ,

place = {United States},

year = {2018},

month = {5}

}