## Two-fluid MHD regime of resistive drift-wave instability

## Abstract

Drift instabilities contribute to the formation of edge turbulence and zonal flows and thus the anomalous transport in tokamaks. Experiments often found micro-scale turbulence strongly coupled with large-scale magnetohydrodynamic (MHD) processes, whereas a general framework has been lacking that can cover both regimes, in particular, their coupling. Here, the linear resistive drift wave instability is investigated using a full 2-fluid MHD model, as well as its numerical implementation in the NIMROD code. Both analytical and numerical analyses reveal a macro-scale global drift wave eigenmode coupled with MHD dynamics and illustrate a non-monotonic dispersion relation with respect to both perpendicular and parallel wavenumbers. NIMROD findings also reveal an edge-localized behavior in the radial mode structure as the azimuthal mode number increases, implying the dependence of the 2-fluid effects due to the inhomogeneous density profile. The edge-localization introduces a non-trivial dependence of the effective perpendicular wavenumber to the perpendicular mode number, which may explain the quantitative difference between the global dispersion relation and its local approximation from the conventional local theory.

- Authors:

- Univ. of Science and Technology of China, Hefei (China)
- Univ. of Science and Technology of China, Hefei (China); Univ. of Wisconsin, Madison, WI (United States)

- Publication Date:

- Research Org.:
- Univ. of Wisconsin, Madison, WI (United States); Univ. of California, Oakland, CA (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division

- OSTI Identifier:
- 1540245

- Alternate Identifier(s):
- OSTI ID: 1474774

- Grant/Contract Number:
- FC02-08ER54975; FG02-86ER53218; AC02-05CH11231

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physics of Plasmas

- Additional Journal Information:
- Journal Volume: 25; Journal Issue: 9; Journal ID: ISSN 1070-664X

- Publisher:
- American Institute of Physics (AIP)

- Country of Publication:
- United States

- Language:
- English

### Citation Formats

```
Yang, Shangchuan, Zhu, Ping, Xie, Jinlin, and Liu, Wandong. Two-fluid MHD regime of resistive drift-wave instability. United States: N. p., 2018.
Web. doi:10.1063/1.5043323.
```

```
Yang, Shangchuan, Zhu, Ping, Xie, Jinlin, & Liu, Wandong. Two-fluid MHD regime of resistive drift-wave instability. United States. doi:10.1063/1.5043323.
```

```
Yang, Shangchuan, Zhu, Ping, Xie, Jinlin, and Liu, Wandong. Fri .
"Two-fluid MHD regime of resistive drift-wave instability". United States. doi:10.1063/1.5043323. https://www.osti.gov/servlets/purl/1540245.
```

```
@article{osti_1540245,
```

title = {Two-fluid MHD regime of resistive drift-wave instability},

author = {Yang, Shangchuan and Zhu, Ping and Xie, Jinlin and Liu, Wandong},

abstractNote = {Drift instabilities contribute to the formation of edge turbulence and zonal flows and thus the anomalous transport in tokamaks. Experiments often found micro-scale turbulence strongly coupled with large-scale magnetohydrodynamic (MHD) processes, whereas a general framework has been lacking that can cover both regimes, in particular, their coupling. Here, the linear resistive drift wave instability is investigated using a full 2-fluid MHD model, as well as its numerical implementation in the NIMROD code. Both analytical and numerical analyses reveal a macro-scale global drift wave eigenmode coupled with MHD dynamics and illustrate a non-monotonic dispersion relation with respect to both perpendicular and parallel wavenumbers. NIMROD findings also reveal an edge-localized behavior in the radial mode structure as the azimuthal mode number increases, implying the dependence of the 2-fluid effects due to the inhomogeneous density profile. The edge-localization introduces a non-trivial dependence of the effective perpendicular wavenumber to the perpendicular mode number, which may explain the quantitative difference between the global dispersion relation and its local approximation from the conventional local theory.},

doi = {10.1063/1.5043323},

journal = {Physics of Plasmas},

number = 9,

volume = 25,

place = {United States},

year = {2018},

month = {9}

}