## Nonlinear dynamics of beta-induced Alfvén eigenmode in tokamak

## Abstract

The beta-induced Alfvén eigenmode (BAE) excited by energetic particles in toroidal plasmas is studied in the global gyrokinetic simulations. It is found that the nonlinear BAE dynamics depends on the deviation from the marginality. In the strongly driven case, the mode exhibits a bursting state with fast and repetitive chirping. The nonlinear saturation is determined by the thermal ion nonlinearity and has no clear dependence on the linear growth rate. In the weakly driven case, the mode reaches a nearly steady state with small frequency chirping. The nonlinear dynamics is dominated by the energetic particle nonlinearity. In both cases, the nonlinear intensity oscillation and frequency chirping are correlated with the evolution of the coherent structures in the energetic particle phase space. Due to the radial variation of the mode amplitude and the radially asymmetric guiding center dynamics, the wave-particle interaction in the toroidal geometry is much more complex than the conventional one-dimensional wave-particle interaction paradigm.

- Authors:

- Peking Univ., Beijing (China); Univ. of California, Irvine, CA (United States)
- Univ. of California, Irvine, CA (United States)
- Zhejiang Univ., Hangzhou (China)
- Univ. of Science and Technology of China, Hefei (China)

- Publication Date:

- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)

- Sponsoring Org.:
- USDOE Office of Science (SC)

- OSTI Identifier:
- 1565000

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physics of Plasmas

- Additional Journal Information:
- Journal Volume: 20; 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; Physics

### Citation Formats

```
Zhang, H. S., Lin, Z., Deng, W., Holod, I., Wang, Z. X., Xiao, Y., and Zhang, W. L. Nonlinear dynamics of beta-induced Alfvén eigenmode in tokamak. United States: N. p., 2013.
Web. doi:10.1063/1.4776698.
```

```
Zhang, H. S., Lin, Z., Deng, W., Holod, I., Wang, Z. X., Xiao, Y., & Zhang, W. L. Nonlinear dynamics of beta-induced Alfvén eigenmode in tokamak. United States. doi:10.1063/1.4776698.
```

```
Zhang, H. S., Lin, Z., Deng, W., Holod, I., Wang, Z. X., Xiao, Y., and Zhang, W. L. Tue .
"Nonlinear dynamics of beta-induced Alfvén eigenmode in tokamak". United States. doi:10.1063/1.4776698. https://www.osti.gov/servlets/purl/1565000.
```

```
@article{osti_1565000,
```

title = {Nonlinear dynamics of beta-induced Alfvén eigenmode in tokamak},

author = {Zhang, H. S. and Lin, Z. and Deng, W. and Holod, I. and Wang, Z. X. and Xiao, Y. and Zhang, W. L.},

abstractNote = {The beta-induced Alfvén eigenmode (BAE) excited by energetic particles in toroidal plasmas is studied in the global gyrokinetic simulations. It is found that the nonlinear BAE dynamics depends on the deviation from the marginality. In the strongly driven case, the mode exhibits a bursting state with fast and repetitive chirping. The nonlinear saturation is determined by the thermal ion nonlinearity and has no clear dependence on the linear growth rate. In the weakly driven case, the mode reaches a nearly steady state with small frequency chirping. The nonlinear dynamics is dominated by the energetic particle nonlinearity. In both cases, the nonlinear intensity oscillation and frequency chirping are correlated with the evolution of the coherent structures in the energetic particle phase space. Due to the radial variation of the mode amplitude and the radially asymmetric guiding center dynamics, the wave-particle interaction in the toroidal geometry is much more complex than the conventional one-dimensional wave-particle interaction paradigm.},

doi = {10.1063/1.4776698},

journal = {Physics of Plasmas},

number = 1,

volume = 20,

place = {United States},

year = {2013},

month = {1}

}

*Citation information provided by*

Web of Science

Web of Science