# Optimisation of confinement in a fusion reactor using a nonlinear turbulence model

## Abstract

The confinement of heat in the core of a magnetic fusion reactor is optimised using a multidimensional optimisation algorithm. For the first time in such a study, the loss of heat due to turbulence is modelled at every stage using first-principles nonlinear simulations which accurately capture the turbulent cascade and large-scale zonal flows. The simulations utilise a novel approach, with gyrofluid treatment of the small-scale drift waves and gyrokinetic treatment of the large-scale zonal flows. A simple near-circular equilibrium with standard parameters is chosen as the initial condition. The figure of merit, fusion power per unit volume, is calculated, and then two control parameters, the elongation and triangularity of the outer flux surface, are varied, with the algorithm seeking to optimise the chosen figure of merit. A twofold increase in the plasma power per unit volume is achieved by moving to higher elongation and strongly negative triangularity.

- Authors:

- Publication Date:

- Research Org.:
- Krell Institute, Ames, IA (United States)

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

- OSTI Identifier:
- 1538938

- DOE Contract Number:
- FG02-97ER25308

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Plasma Physics

- Additional Journal Information:
- Journal Volume: 84; Journal Issue: 2; Journal ID: ISSN 0022-3778

- Publisher:
- Cambridge University Press

- Country of Publication:
- United States

- Language:
- English

- Subject:
- Physics

### Citation Formats

```
Highcock, E. G., Mandell, N. R., Barnes, M., and Dorland, W.
```*Optimisation of confinement in a fusion reactor using a nonlinear turbulence model*. United States: N. p., 2018.
Web. doi:10.1017/s002237781800034x.

```
Highcock, E. G., Mandell, N. R., Barnes, M., & Dorland, W.
```*Optimisation of confinement in a fusion reactor using a nonlinear turbulence model*. United States. doi:10.1017/s002237781800034x.

```
Highcock, E. G., Mandell, N. R., Barnes, M., and Dorland, W. Sun .
"Optimisation of confinement in a fusion reactor using a nonlinear turbulence model". United States. doi:10.1017/s002237781800034x.
```

```
@article{osti_1538938,
```

title = {Optimisation of confinement in a fusion reactor using a nonlinear turbulence model},

author = {Highcock, E. G. and Mandell, N. R. and Barnes, M. and Dorland, W.},

abstractNote = {The confinement of heat in the core of a magnetic fusion reactor is optimised using a multidimensional optimisation algorithm. For the first time in such a study, the loss of heat due to turbulence is modelled at every stage using first-principles nonlinear simulations which accurately capture the turbulent cascade and large-scale zonal flows. The simulations utilise a novel approach, with gyrofluid treatment of the small-scale drift waves and gyrokinetic treatment of the large-scale zonal flows. A simple near-circular equilibrium with standard parameters is chosen as the initial condition. The figure of merit, fusion power per unit volume, is calculated, and then two control parameters, the elongation and triangularity of the outer flux surface, are varied, with the algorithm seeking to optimise the chosen figure of merit. A twofold increase in the plasma power per unit volume is achieved by moving to higher elongation and strongly negative triangularity.},

doi = {10.1017/s002237781800034x},

journal = {Journal of Plasma Physics},

issn = {0022-3778},

number = 2,

volume = 84,

place = {United States},

year = {2018},

month = {4}

}