# Physics Basis for a Spherical Torus Power Plant

## Abstract

The spherical torus, or low-aspect-ratio tokamak, is considered as the basis for a fusion power plant. A special class of wall-stabilized high-beta high-bootstrap fraction low-aspect-ratio tokamak equilibrium are analyzed with respect to MHD stability, bootstrap current and external current drive, poloidal field system requirements, power and particle exhaust and plasma operating regime. Overall systems optimization leads to a choice of aspect ratio A = 1:6, plasma elongation kappa = 3:4, and triangularity delta = 0:64. The design value for the plasma toroidal beta is 50%, corresponding to beta N = 7:4, which is 10% below the ideal stability limit. The bootstrap fraction of 99% greatly alleviates the current drive requirements, which are met by tangential neutral beam injection. The design is such that 45% of the thermal power is radiated in the plasma by Bremsstrahlung and trace Krypton, with Neon in the scrapeoff layer radiating the remainder.

- Authors:

- Publication Date:

- Research Org.:
- Princeton Plasma Physics Lab., NJ (US)

- Sponsoring Org.:
- USDOE Office of Energy Research (ER) (US)

- OSTI Identifier:
- 14763

- Report Number(s):
- PPPL-3392

TRN: US0106786

- DOE Contract Number:
- AC02-76CH03073

- Resource Type:
- Technical Report

- Resource Relation:
- Other Information: PBD: 1 Nov 1999

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASPECT RATIO; BEAM INJECTION; BOOTSTRAP CURRENT; BREMSSTRAHLUNG; PLASMA SCRAPE-OFF LAYER; KRYPTON; NEON; THERMONUCLEAR POWER PLANTS; STABILITY; SPHEROMAK DEVICES

### Citation Formats

```
C.E. Kessel, J. Menard, S.C. Jardin, T.K. Mau, and et al.
```*Physics Basis for a Spherical Torus Power Plant*. United States: N. p., 1999.
Web. doi:10.2172/14763.

```
C.E. Kessel, J. Menard, S.C. Jardin, T.K. Mau, & et al.
```*Physics Basis for a Spherical Torus Power Plant*. United States. doi:10.2172/14763.

```
C.E. Kessel, J. Menard, S.C. Jardin, T.K. Mau, and et al. Mon .
"Physics Basis for a Spherical Torus Power Plant". United States.
doi:10.2172/14763. https://www.osti.gov/servlets/purl/14763.
```

```
@article{osti_14763,
```

title = {Physics Basis for a Spherical Torus Power Plant},

author = {C.E. Kessel and J. Menard and S.C. Jardin and T.K. Mau and et al},

abstractNote = {The spherical torus, or low-aspect-ratio tokamak, is considered as the basis for a fusion power plant. A special class of wall-stabilized high-beta high-bootstrap fraction low-aspect-ratio tokamak equilibrium are analyzed with respect to MHD stability, bootstrap current and external current drive, poloidal field system requirements, power and particle exhaust and plasma operating regime. Overall systems optimization leads to a choice of aspect ratio A = 1:6, plasma elongation kappa = 3:4, and triangularity delta = 0:64. The design value for the plasma toroidal beta is 50%, corresponding to beta N = 7:4, which is 10% below the ideal stability limit. The bootstrap fraction of 99% greatly alleviates the current drive requirements, which are met by tangential neutral beam injection. The design is such that 45% of the thermal power is radiated in the plasma by Bremsstrahlung and trace Krypton, with Neon in the scrapeoff layer radiating the remainder.},

doi = {10.2172/14763},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Mon Nov 01 00:00:00 EST 1999},

month = {Mon Nov 01 00:00:00 EST 1999}

}