## This content will become publicly available on October 15, 2020

# Cross-verification of neoclassical transport solutions from XGCa against NEO

## Abstract

Radial neoclassical transport from the global gyrokinetic code XGC has been cross-verified against the local drift-kinetic neoclassical code NEO in NEO's local regime using a Grad-Shafranov equilibrium with a circular boundary. XGC shows excellent agreement with NEO, except for a difference of approximately 10% in the ion heat flux. Close investigation reveals that this difference is due to the simplification in NEO to use the same Coulomb logarithm ln Λ to represent all particle species, while XGC uses different formulas for collisions between different species. When XGC uses NEO's Coulomb logarithm, excellent agreement in the ion heat flux is recovered. Here, the present work not only crossverifies the equation solvers in two codes, but also verifies that the gyrokinetic and the drift-kinetic equations agree and that the linearized and nonlinear Coulomb collision operators agree in the mild gradient, local regime.

- Authors:

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

- Publication Date:

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

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1573464

- Alternate Identifier(s):
- OSTI ID: 1570494

- Grant/Contract Number:
- AC02-09CH11466; FC02-04ER54698; AC02-06CH11357; AC02-05CH11231

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physics of Plasmas

- Additional Journal Information:
- Journal Volume: 26; Journal Issue: 10; 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

```
Hager, R., Dominski, J., and Chang, C. S. Cross-verification of neoclassical transport solutions from XGCa against NEO. United States: N. p., 2019.
Web. doi:10.1063/1.5121308.
```

```
Hager, R., Dominski, J., & Chang, C. S. Cross-verification of neoclassical transport solutions from XGCa against NEO. United States. doi:10.1063/1.5121308.
```

```
Hager, R., Dominski, J., and Chang, C. S. Tue .
"Cross-verification of neoclassical transport solutions from XGCa against NEO". United States. doi:10.1063/1.5121308.
```

```
@article{osti_1573464,
```

title = {Cross-verification of neoclassical transport solutions from XGCa against NEO},

author = {Hager, R. and Dominski, J. and Chang, C. S.},

abstractNote = {Radial neoclassical transport from the global gyrokinetic code XGC has been cross-verified against the local drift-kinetic neoclassical code NEO in NEO's local regime using a Grad-Shafranov equilibrium with a circular boundary. XGC shows excellent agreement with NEO, except for a difference of approximately 10% in the ion heat flux. Close investigation reveals that this difference is due to the simplification in NEO to use the same Coulomb logarithm ln Λ to represent all particle species, while XGC uses different formulas for collisions between different species. When XGC uses NEO's Coulomb logarithm, excellent agreement in the ion heat flux is recovered. Here, the present work not only crossverifies the equation solvers in two codes, but also verifies that the gyrokinetic and the drift-kinetic equations agree and that the linearized and nonlinear Coulomb collision operators agree in the mild gradient, local regime.},

doi = {10.1063/1.5121308},

journal = {Physics of Plasmas},

number = 10,

volume = 26,

place = {United States},

year = {2019},

month = {10}

}

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