# 3D Equilibrium Effects Due to RMP Application on DIII-D

## Abstract

The mitigation and suppression of edge localized modes (ELMs) through application of resonant magnetic perturbations (RMPs) in Tokamak plasmas is a well documented phenomenon [1]. Vacuum calculations suggest the formation of edge islands and stochastic regions when RMPs are applied to the axisymmetric equilibria. Self-consistent calculations of the plasma equilibrium with the VMEC [2] and SPEC [3] codes have been performed for an up-down symmetric shot (142603) in DIII-D. In these codes, a self-consistent calculation of the plasma response due to the RMP coils is calculated. The VMEC code globally enforces the constraints of ideal MHD; consequently, a continuously nested family of flux surfaces is enforced throughout the plasma domain. This approach necessarily precludes the observation of islands or field-line chaos. The SPEC code relaxes the constraints of ideal MHD locally, and allows for islands and field line chaos at or near the rational surfaces. Equilibria with finite pressure gradients are approximated by a set of discrete "ideal-interfaces" at the most irrational flux surfaces and where the strongest pressure gradients are observed. Both the VMEC and SPEC calculations are initialized from EFIT reconstructions of the plasma that are consistent with the experimental pressure and current profiles. A 3D reconstruction usingmore »

- Authors:

- Publication Date:

- Research Org.:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC)

- OSTI Identifier:
- 1057660

- Report Number(s):
- PPPL-4772

- DOE Contract Number:
- DE-ACO2-09CH11466

- Resource Type:
- Conference

- Resource Relation:
- Conference: 39th European Physical Society Conference on Plasma Physics, Stockholm, Sweden (June 2012)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Edge-localized Mode (ELM) Equilibrium MHD - Toroidal

### Citation Formats

```
S. Lazerson, E. Lazarus, S. Hudson, N. Pablant and D. Gates.
```*3D Equilibrium Effects Due to RMP Application on DIII-D*. United States: N. p., 2012.
Web.

```
S. Lazerson, E. Lazarus, S. Hudson, N. Pablant and D. Gates.
```*3D Equilibrium Effects Due to RMP Application on DIII-D*. United States.

```
S. Lazerson, E. Lazarus, S. Hudson, N. Pablant and D. Gates. Wed .
"3D Equilibrium Effects Due to RMP Application on DIII-D". United States. https://www.osti.gov/servlets/purl/1057660.
```

```
@article{osti_1057660,
```

title = {3D Equilibrium Effects Due to RMP Application on DIII-D},

author = {S. Lazerson, E. Lazarus, S. Hudson, N. Pablant and D. Gates},

abstractNote = {The mitigation and suppression of edge localized modes (ELMs) through application of resonant magnetic perturbations (RMPs) in Tokamak plasmas is a well documented phenomenon [1]. Vacuum calculations suggest the formation of edge islands and stochastic regions when RMPs are applied to the axisymmetric equilibria. Self-consistent calculations of the plasma equilibrium with the VMEC [2] and SPEC [3] codes have been performed for an up-down symmetric shot (142603) in DIII-D. In these codes, a self-consistent calculation of the plasma response due to the RMP coils is calculated. The VMEC code globally enforces the constraints of ideal MHD; consequently, a continuously nested family of flux surfaces is enforced throughout the plasma domain. This approach necessarily precludes the observation of islands or field-line chaos. The SPEC code relaxes the constraints of ideal MHD locally, and allows for islands and field line chaos at or near the rational surfaces. Equilibria with finite pressure gradients are approximated by a set of discrete "ideal-interfaces" at the most irrational flux surfaces and where the strongest pressure gradients are observed. Both the VMEC and SPEC calculations are initialized from EFIT reconstructions of the plasma that are consistent with the experimental pressure and current profiles. A 3D reconstruction using the STELLOPT code, which fits VMEC equilibria to experimental measurements, has also been performed. Comparisons between the equilibria generated by the 3D codes and between STELLOPT and EFIT are presented.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {2012},

month = {6}

}