A Fokker-Planck collision model for gyrokinetic simulations in stellarators
Abstract
We describe an implementation of the gyrokinetic linearised Fokker-Planck collision operator that satisfies pertinent conservation laws and is valid at arbitrary collisionalities. The differential test-particle component of the operator is exact; the implementation of the integro-differential field-particle component relies on the spherical harmonic and Laguerre polynomial expansion introduced by Hirshman and Sigmar. Properties and numerical methods of the implementation in the δf -gyrokinetic code stella are discussed, and benchmarks against the collision model of the gyrokinetic solver GS2 are provided. Preliminary results of collisional gyrokinetic simulations of microinstabilities in the Wendelstein-7X stellarator are also presented.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- 2020
- Bibcode:
- 2020APS..DPPV14007V