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# A simple model for perturbative kinetic particle resonances in tokamaks

## Abstract

Resonances driven by particle distribution gradients are studied in a simple statistical model which does not involve advancing individual particles due to the interaction with the mode. The phase-space structure of resonances and the associated modification of density profiles in tokamaks are due to equilibration between the bounce averaging of particles within the resonance, which tends to locally flatten the distribution, particle collisions, which tend to re-establish the original density gradients, and wave background damping, which extracts energy from the mode. Modes are perturbatively driven while the distribution is irreversibly modified due to diffusion within the resonance, where local properties of the equilibrium and particle distribution are sufficient to determine the time evolution of a mode. As a result, simulations replicate the expected scaling with the collision frequency of mode saturation amplitudes and collisional broadening of the density modification and give reasonable agreement with saturation amplitudes given by full guiding center simulations.

- Authors:

- Princeton Univ., Princeton, NJ (United States). Princeton Plasma Physics Lab

- Publication Date:

- Research Org.:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1558789

- Grant/Contract Number:
- AC02-09CH11466

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physics of Plasmas

- Additional Journal Information:
- Journal Volume: 26; Journal Issue: 4; 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

### Citation Formats

```
White, R. B., and Duarte, V. N. A simple model for perturbative kinetic particle resonances in tokamaks. United States: N. p., 2019.
Web. doi:10.1063/1.5092965.
```

```
White, R. B., & Duarte, V. N. A simple model for perturbative kinetic particle resonances in tokamaks. United States. doi:10.1063/1.5092965.
```

```
White, R. B., and Duarte, V. N. Wed .
"A simple model for perturbative kinetic particle resonances in tokamaks". United States. doi:10.1063/1.5092965.
```

```
@article{osti_1558789,
```

title = {A simple model for perturbative kinetic particle resonances in tokamaks},

author = {White, R. B. and Duarte, V. N.},

abstractNote = {Resonances driven by particle distribution gradients are studied in a simple statistical model which does not involve advancing individual particles due to the interaction with the mode. The phase-space structure of resonances and the associated modification of density profiles in tokamaks are due to equilibration between the bounce averaging of particles within the resonance, which tends to locally flatten the distribution, particle collisions, which tend to re-establish the original density gradients, and wave background damping, which extracts energy from the mode. Modes are perturbatively driven while the distribution is irreversibly modified due to diffusion within the resonance, where local properties of the equilibrium and particle distribution are sufficient to determine the time evolution of a mode. As a result, simulations replicate the expected scaling with the collision frequency of mode saturation amplitudes and collisional broadening of the density modification and give reasonable agreement with saturation amplitudes given by full guiding center simulations.},

doi = {10.1063/1.5092965},

journal = {Physics of Plasmas},

number = 4,

volume = 26,

place = {United States},

year = {2019},

month = {4}

}

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