# Nonlinear parallel momentum transport in strong electrostatic turbulence

## Abstract

Most existing theoretical studies of momentum transport focus on calculating the Reynolds stress based on quasilinear theory, without considering the nonlinear momentum flux-〈v{sup ~}{sub r}n{sup ~}u{sup ~}{sub ∥}〉. However, a recent experiment on TORPEX found that the nonlinear toroidal momentum flux induced by blobs makes a significant contribution as compared to the Reynolds stress [Labit et al., Phys. Plasmas 18, 032308 (2011)]. In this work, the nonlinear parallel momentum flux in strong electrostatic turbulence is calculated by using a three dimensional Hasegawa-Mima equation, which is relevant for tokamak edge turbulence. It is shown that the nonlinear diffusivity is smaller than the quasilinear diffusivity from Reynolds stress. However, the leading order nonlinear residual stress can be comparable to the quasilinear residual stress, and so may be important to intrinsic rotation in tokamak edge plasmas. A key difference from the quasilinear residual stress is that parallel fluctuation spectrum asymmetry is not required for nonlinear residual stress.

- Authors:

- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)
- Center for Momentum Transport and Flow Organization and Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, California 92093-0424 (United States)

- Publication Date:

- OSTI Identifier:
- 22410305

- Resource Type:
- Journal Article

- Journal Name:
- Physics of Plasmas

- Additional Journal Information:
- Journal Volume: 22; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASYMMETRY; EDGE LOCALIZED MODES; NONLINEAR PROBLEMS; PLASMA; QUASILINEAR PROBLEMS; RESIDUAL STRESSES; REYNOLDS NUMBER; ROTATING PLASMA; SPECTRA; THREE-DIMENSIONAL CALCULATIONS; TOKAMAK DEVICES; TURBULENCE

### Citation Formats

```
Wang, Lu, E-mail: luwang@hust.edu.cn, Wen, Tiliang, and Diamond, P. H.
```*Nonlinear parallel momentum transport in strong electrostatic turbulence*. United States: N. p., 2015.
Web. doi:10.1063/1.4919622.

```
Wang, Lu, E-mail: luwang@hust.edu.cn, Wen, Tiliang, & Diamond, P. H.
```*Nonlinear parallel momentum transport in strong electrostatic turbulence*. United States. doi:10.1063/1.4919622.

```
Wang, Lu, E-mail: luwang@hust.edu.cn, Wen, Tiliang, and Diamond, P. H. Fri .
"Nonlinear parallel momentum transport in strong electrostatic turbulence". United States. doi:10.1063/1.4919622.
```

```
@article{osti_22410305,
```

title = {Nonlinear parallel momentum transport in strong electrostatic turbulence},

author = {Wang, Lu, E-mail: luwang@hust.edu.cn and Wen, Tiliang and Diamond, P. H.},

abstractNote = {Most existing theoretical studies of momentum transport focus on calculating the Reynolds stress based on quasilinear theory, without considering the nonlinear momentum flux-〈v{sup ~}{sub r}n{sup ~}u{sup ~}{sub ∥}〉. However, a recent experiment on TORPEX found that the nonlinear toroidal momentum flux induced by blobs makes a significant contribution as compared to the Reynolds stress [Labit et al., Phys. Plasmas 18, 032308 (2011)]. In this work, the nonlinear parallel momentum flux in strong electrostatic turbulence is calculated by using a three dimensional Hasegawa-Mima equation, which is relevant for tokamak edge turbulence. It is shown that the nonlinear diffusivity is smaller than the quasilinear diffusivity from Reynolds stress. However, the leading order nonlinear residual stress can be comparable to the quasilinear residual stress, and so may be important to intrinsic rotation in tokamak edge plasmas. A key difference from the quasilinear residual stress is that parallel fluctuation spectrum asymmetry is not required for nonlinear residual stress.},

doi = {10.1063/1.4919622},

journal = {Physics of Plasmas},

issn = {1070-664X},

number = 5,

volume = 22,

place = {United States},

year = {2015},

month = {5}

}