# Poloidal rotation driven by nonlinear momentum transport in strong electrostatic turbulence

## Abstract

Virtually, all existing theoretical works on turbulent poloidal momentum transport are based on quasilinear theory. Nonlinear poloidal momentum flux—$$\langle {{\tilde{v}}_{r}}\tilde{n}{{\tilde{v}}_{\theta}}\rangle $$ is universally neglected. However, in the strong turbulence regime where relative fluctuation amplitude is no longer small, quasilinear theory is invalid. This is true at the all-important plasma edge. In this work, nonlinear poloidal momentum flux $$\langle {{\tilde{v}}_{r}}\tilde{n}{{\tilde{v}}_{\theta}}\rangle $$ in strong electrostatic turbulence is calculated using the Hasegawa–Mima equation, and is compared with quasilinear poloidal Reynolds stress. A novel property is that symmetry breaking in fluctuation spectrum is not necessary for a nonlinear poloidal momentum flux. This is fundamentally different from the quasilinear Reynold stress. Furthermore, the comparison implies that the poloidal rotation drive from the radial gradient of nonlinear momentum flux is comparable to that from the quasilinear Reynolds force. Nonlinear poloidal momentum transport in strong electrostatic turbulence is thus not negligible for poloidal rotation drive, and so may be significant to transport barrier formation.

- Authors:

- Publication Date:

- Research Org.:
- Univ. of California, San Diego, CA (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1290304

- Alternate Identifier(s):
- OSTI ID: 1290305; OSTI ID: 1429884

- Grant/Contract Number:
- FG02-04ER54738; 2013GB112002

- Resource Type:
- Journal Article: Published Article

- Journal Name:
- Nuclear Fusion

- Additional Journal Information:
- Journal Name: Nuclear Fusion Journal Volume: 56 Journal Issue: 10; Journal ID: ISSN 0029-5515

- Publisher:
- IOP Publishing

- Country of Publication:
- IAEA

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; poloidal rotation; nonlinear poloidal momentum flux; strong turbulence; Reynolds stress

### Citation Formats

```
Wang, Lu, Wen, Tiliang, and Diamond, P. H.
```*Poloidal rotation driven by nonlinear momentum transport in strong electrostatic turbulence*. IAEA: N. p., 2016.
Web. doi:10.1088/0029-5515/56/10/106017.

```
Wang, Lu, Wen, Tiliang, & Diamond, P. H.
```*Poloidal rotation driven by nonlinear momentum transport in strong electrostatic turbulence*. IAEA. https://doi.org/10.1088/0029-5515/56/10/106017

```
Wang, Lu, Wen, Tiliang, and Diamond, P. H. Thu .
"Poloidal rotation driven by nonlinear momentum transport in strong electrostatic turbulence". IAEA. https://doi.org/10.1088/0029-5515/56/10/106017.
```

```
@article{osti_1290304,
```

title = {Poloidal rotation driven by nonlinear momentum transport in strong electrostatic turbulence},

author = {Wang, Lu and Wen, Tiliang and Diamond, P. H.},

abstractNote = {Virtually, all existing theoretical works on turbulent poloidal momentum transport are based on quasilinear theory. Nonlinear poloidal momentum flux—$\langle {{\tilde{v}}_{r}}\tilde{n}{{\tilde{v}}_{\theta}}\rangle $ is universally neglected. However, in the strong turbulence regime where relative fluctuation amplitude is no longer small, quasilinear theory is invalid. This is true at the all-important plasma edge. In this work, nonlinear poloidal momentum flux $\langle {{\tilde{v}}_{r}}\tilde{n}{{\tilde{v}}_{\theta}}\rangle $ in strong electrostatic turbulence is calculated using the Hasegawa–Mima equation, and is compared with quasilinear poloidal Reynolds stress. A novel property is that symmetry breaking in fluctuation spectrum is not necessary for a nonlinear poloidal momentum flux. This is fundamentally different from the quasilinear Reynold stress. Furthermore, the comparison implies that the poloidal rotation drive from the radial gradient of nonlinear momentum flux is comparable to that from the quasilinear Reynolds force. Nonlinear poloidal momentum transport in strong electrostatic turbulence is thus not negligible for poloidal rotation drive, and so may be significant to transport barrier formation.},

doi = {10.1088/0029-5515/56/10/106017},

url = {https://www.osti.gov/biblio/1290304},
journal = {Nuclear Fusion},

issn = {0029-5515},

number = 10,

volume = 56,

place = {IAEA},

year = {2016},

month = {8}

}

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