Fluid and gyrokinetic modelling of particle transport in plasmas with hollow density profiles
Conference poster, 2016

Hollow density profiles occur in connection with pellet fuelling and L to H transitions. A positive density gradient could potentially stabilize the turbulence or change the relation between convective and diffusive fluxes, thereby reducing the turbulent transport of particles towards the center, making the fuelling scheme inefficient. In the present work, the particle transport driven by ITG/TE mode turbulence in regions of hollow density profiles is studied by fluid as well as gyrokinetic simulations. The fluid model used, an extended version of the Weiland transport model, Extended Drift Wave Model (EDWM), incorporates an arbitrary number of ion species in a multi-fluid description, and an extended wavelength spectrum. The fluid model, which is fast and hence suitable for use in predictive simulations, is compared to gyrokinetic simulations using the code GENE. Typical tokamak parameters are used based on the Cyclone Base Case. Parameter scans in key plasma parameters like plasma β, R/LT , and magnetic shear are investigated. It is found that β in particular has a stabilizing effect in the negative R/Ln region, both nonlinear GENE and EDWM show a decrease in inward flux for negative R/Ln and a change of direction from inward to outward for positive R/Ln . This might have serious consequences for pellet fuelling of high β plasmas.

Author

Daniel Tegnered

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Michael Oberparleiter

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Hans Nordman

Chalmers, Earth and Space Sciences

Pär Strand

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

THEORY OF FUSION PLASMAS JOINT VARENNA - LAUSANNE INTERNATIONAL WORKSHOP, 2016

Driving Forces

Sustainable development

Areas of Advance

Energy

Subject Categories

Fusion, Plasma and Space Physics

More information

Created

10/7/2017