Impact of fast ions on density peaking in JET: fluid and gyrokinetic modeling
Journal article, 2019

The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position rho(t) = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile.

fluid

particle transport

fast ions

gyrokinetic

Author

Fredrik Eriksson

Chalmers, Physics, Materials and Surface Theory

Michael Oberparleiter

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Plasma Physics and Fusion Energy

Andreas Skyman

Chalmers, Space, Earth and Environment, Microwave and Optical Remote Sensing, Global Environmental Measurements and Modelling

Hans Nordman

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Plasma Physics and Fusion Energy

Pär Strand

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Plasma Physics and Fusion Energy

Antti Salmi

Technical Research Centre of Finland (VTT)

Tuomas Tala

Technical Research Centre of Finland (VTT)

Plasma Physics and Controlled Fusion

0741-3335 (ISSN) 1361-6587 (eISSN)

Vol. 61 7 075008

Subject Categories

Other Physics Topics

Fluid Mechanics and Acoustics

Fusion, Plasma and Space Physics

DOI

10.1088/1361-6587/ab1e65

More information

Latest update

11/19/2019