# 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:

- Huazhong University of Science and Technology, Wuhan (China). State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engneering
- University of California at San Diego, La Jolla, CA (United States). Center for Momentum Transport and Flow Organization and Center for Astrophysics and Space Sciences

- 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 Volume: 56; Journal Issue: 10; Journal ID: ISSN 0029-5515

- Publisher:
- IOP Science

- Country of Publication:
- United States

- 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*. United States: 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*. United States. doi: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". United States.
doi: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},

journal = {Nuclear Fusion},

number = 10,

volume = 56,

place = {United States},

year = {Thu Aug 11 00:00:00 EDT 2016},

month = {Thu Aug 11 00:00:00 EDT 2016}

}

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