Impact of fast ions on density peaking in JET: Fluid and gyrokinetic modeling

F. Eriksson, M. Oberparleiter, A. Skyman, H. Nordman, P. Strand, A. Salmi, T. Tala, JET Contributors

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)

Abstract

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 ρ 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.

Original languageEnglish
Article number075008
Number of pages10
JournalPlasma Physics and Controlled Fusion
Volume61
Issue number7
DOIs
Publication statusPublished - 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • Fast ions
  • Fluid
  • Gyrokinetic
  • Particle transport

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