## Centrifugal particle confinement in mirror geometry

## Abstract

The use of supersonic rotation of a plasma in mirror geometry has distinct advantages for thermonuclear fusion. The device is steady state, there are no disruptions, the loss cone is almost closed, sheared rotation stabilizes magnetohydrodynamic instabilities as well as plasma turbulence, there are no runaway electrons, and the coil configuration is simple. In this work, we examine the effect of rotation on mirror confinement using a full cyclotron orbit code. The full cyclotron simulations give a much more complete description of the particle energy distribution and losses than the use of guiding center equations. Both collisionless loss as a function of rotation and the effect of collisions are investigated. Although the cross field diffusion is classical, we find that the local rotating Maxwellian is increased to higher energy, increasing the fusion rate and also enhancing the radial diffusion. We find a loss channel not envisioned with a guiding center treatment, but a design can be chosen that can satisfy the Lawson criterion for ions. Of course, the rotation has a minimal effect on the alpha particle birth distribution, so there is initially loss through the usual loss cone, just as in a mirror with no rotation. However after thismore »

- Authors:

- Princeton Univ., Princeton, NJ (United States). Plasma Physics Lab.
- Univ. of Maryland, College Park, MD (United States). Dept. of Physics
- Saint Michael's College, Colchester, VT (United States). Dept. of Physics

- Publication Date:

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

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1464670

- Alternate Identifier(s):
- OSTI ID: 1418723

- Grant/Contract Number:
- AC02-09CH11466

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physics of Plasmas

- Additional Journal Information:
- Journal Volume: 25; Journal Issue: 1; Journal ID: ISSN 1070-664X

- Publisher:
- American Institute of Physics (AIP)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

### Citation Formats

```
White, Roscoe, Hassam, Adil, and Brizard, Alain. Centrifugal particle confinement in mirror geometry. United States: N. p., 2018.
Web. doi:10.1063/1.5003359.
```

```
White, Roscoe, Hassam, Adil, & Brizard, Alain. Centrifugal particle confinement in mirror geometry. United States. doi:10.1063/1.5003359.
```

```
White, Roscoe, Hassam, Adil, and Brizard, Alain. Tue .
"Centrifugal particle confinement in mirror geometry". United States. doi:10.1063/1.5003359. https://www.osti.gov/servlets/purl/1464670.
```

```
@article{osti_1464670,
```

title = {Centrifugal particle confinement in mirror geometry},

author = {White, Roscoe and Hassam, Adil and Brizard, Alain},

abstractNote = {The use of supersonic rotation of a plasma in mirror geometry has distinct advantages for thermonuclear fusion. The device is steady state, there are no disruptions, the loss cone is almost closed, sheared rotation stabilizes magnetohydrodynamic instabilities as well as plasma turbulence, there are no runaway electrons, and the coil configuration is simple. In this work, we examine the effect of rotation on mirror confinement using a full cyclotron orbit code. The full cyclotron simulations give a much more complete description of the particle energy distribution and losses than the use of guiding center equations. Both collisionless loss as a function of rotation and the effect of collisions are investigated. Although the cross field diffusion is classical, we find that the local rotating Maxwellian is increased to higher energy, increasing the fusion rate and also enhancing the radial diffusion. We find a loss channel not envisioned with a guiding center treatment, but a design can be chosen that can satisfy the Lawson criterion for ions. Of course, the rotation has a minimal effect on the alpha particle birth distribution, so there is initially loss through the usual loss cone, just as in a mirror with no rotation. However after this loss, the alphas slow down on the electrons with little pitch angle scattering until reaching low energy, so over half of the initial alpha energy is transferred to the electrons. The important problem of energy confinement, with losses primarily through the electron channel, is not addressed in this work. In conclusion, we also discuss the use of rotating mirror geometry to produce an ion thruster.},

doi = {10.1063/1.5003359},

journal = {Physics of Plasmas},

number = 1,

volume = 25,

place = {United States},

year = {2018},

month = {1}

}