# Equilibrium, stability, and deeply trapped energetic particle confinement calculations for I = 2 torsatron/heliotron configurations

## Abstract

This paper studies confinement properties of 1 = 2 torsatron/heliotron configurations with number of toroidal field periods, M, in the range of 10 to 14. This involves the calculation of zero-current and flux-conserving equilibria; stability against Mercier modes and low-n ideal modes, with n denoting the toroidal mode number; and orbit confinement of deeply trapped energetic particles. Optimization of both magnetohydrodynamic (MHD) and transport properties is pursued under the condition of plasma aspect ratio A = R/a {ge} 7, with R denoting the major radius and a the average plasma radius. For configurations with M, {le} 12, an average MHD beta limit of 4 to 5% is possible. The addition of a quadrupole field improves the confinement of trapped particles at zero pressure, but particle losses increase with increasing beta. This loss is less severe if the vacuum magnetic axis is shifted slightly inward. A configuration with M = 10, a coil pitch parameter p{sub c} in the range 1.25 to 1.30, and an added quadrupole field satisfies the beta and energetic particle confinement requirements for the next generation of large torsatron/heliotron devices.

- Authors:

- (Kyoto Univ., Plasma Physics Lab., Gokasho, Uji, Kyoto (JP))
- (Oak Ridge National Lab., Oak Ridge, TN (US))
- (Univ. Complutense and Asociacion EURATOM/CIEMAT, 28040 Madrid (ES))

- Publication Date:

- OSTI Identifier:
- 5002797

- DOE Contract Number:
- AC05-84OR21400

- Resource Type:
- Journal Article

- Journal Name:
- Fusion Technology; (United States)

- Additional Journal Information:
- Journal Volume: 19:2; Journal ID: ISSN 0748-1896

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; HELIOTRON; MAGNETOHYDRODYNAMICS; HIGH-BETA PLASMA; TRAPPED-PARTICLE INSTABILITY; PLASMA CONFINEMENT; CALCULATION METHODS; TORSATRON STELLARATORS; EQUILIBRIUM PLASMA; OPTIMIZATION; PLASMA DRIFT; QUADRUPOLAR CONFIGURATIONS; CLOSED CONFIGURATIONS; CLOSED PLASMA DEVICES; CONFINEMENT; FLUID MECHANICS; HYDRODYNAMICS; INSTABILITY; MAGNETIC FIELD CONFIGURATIONS; MECHANICS; MULTIPOLAR CONFIGURATIONS; PLASMA; PLASMA INSTABILITY; PLASMA MACROINSTABILITIES; STELLARATORS; THERMONUCLEAR DEVICES; 700202* - Fusion Power Plant Technology- Magnet Coils & Fields; 700200 - Fusion Energy- Fusion Power Plant Technology; 640430 - Fluid Physics- Magnetohydrodynamics; 700107 - Fusion Energy- Plasma Research- Instabilities

### Citation Formats

```
Nakamura, Y., Wakatani, M., Leboeuf, J.N., Carreras, B.A., Dominguez, N., Holmes, J.A., Lynch, V.E., Painter, S.L., and Garcia, L.
```*Equilibrium, stability, and deeply trapped energetic particle confinement calculations for I = 2 torsatron/heliotron configurations*. United States: N. p., 1991.
Web.

```
Nakamura, Y., Wakatani, M., Leboeuf, J.N., Carreras, B.A., Dominguez, N., Holmes, J.A., Lynch, V.E., Painter, S.L., & Garcia, L.
```*Equilibrium, stability, and deeply trapped energetic particle confinement calculations for I = 2 torsatron/heliotron configurations*. United States.

```
Nakamura, Y., Wakatani, M., Leboeuf, J.N., Carreras, B.A., Dominguez, N., Holmes, J.A., Lynch, V.E., Painter, S.L., and Garcia, L. Fri .
"Equilibrium, stability, and deeply trapped energetic particle confinement calculations for I = 2 torsatron/heliotron configurations". United States.
```

```
@article{osti_5002797,
```

title = {Equilibrium, stability, and deeply trapped energetic particle confinement calculations for I = 2 torsatron/heliotron configurations},

author = {Nakamura, Y. and Wakatani, M. and Leboeuf, J.N. and Carreras, B.A. and Dominguez, N. and Holmes, J.A. and Lynch, V.E. and Painter, S.L. and Garcia, L.},

abstractNote = {This paper studies confinement properties of 1 = 2 torsatron/heliotron configurations with number of toroidal field periods, M, in the range of 10 to 14. This involves the calculation of zero-current and flux-conserving equilibria; stability against Mercier modes and low-n ideal modes, with n denoting the toroidal mode number; and orbit confinement of deeply trapped energetic particles. Optimization of both magnetohydrodynamic (MHD) and transport properties is pursued under the condition of plasma aspect ratio A = R/a {ge} 7, with R denoting the major radius and a the average plasma radius. For configurations with M, {le} 12, an average MHD beta limit of 4 to 5% is possible. The addition of a quadrupole field improves the confinement of trapped particles at zero pressure, but particle losses increase with increasing beta. This loss is less severe if the vacuum magnetic axis is shifted slightly inward. A configuration with M = 10, a coil pitch parameter p{sub c} in the range 1.25 to 1.30, and an added quadrupole field satisfies the beta and energetic particle confinement requirements for the next generation of large torsatron/heliotron devices.},

doi = {},

journal = {Fusion Technology; (United States)},

issn = {0748-1896},

number = ,

volume = 19:2,

place = {United States},

year = {1991},

month = {3}

}