Neoclassical Impurity Transport in Stellarator Geometry
Event details
| Date | 03.10.2012 |
| Hour | 15:00 › 16:00 |
| Speaker | Dr. J.M. Garcìa-Regaña, Max-Planck-Institute für Plasmaphysik, Greifswald, Germany |
| Location |
PPB 019
|
| Category | Conferences - Seminars |
The impurity dynamics in stellarators has become an issue of moderate concern due to the, a priori, inherent tendency of the impurities to accumulate in the core when the neoclassical ambipolar radial electric field points inwards (ion root regime). This accumulation can lead to collapse of the plasma due to radiative losses, and thus limit high performance plasma discharges in non-axisymmetric devices.
Theoretically, a quantitative description of the neoclassical impurity transport is complicated by the breakdown of the assumption of small qΦ/T for impurities, where q is the electric charge, T the temperature in energy units, and Φ the electrostatic potential variation within the flux surface.
The present work describes quantitatively the particle transport of impurities in the frame of local neoclassical theory when qΦ/T = O(1) in the Large Helical Device (LHD) stellarator. The central numerical tool used to describe the impurity dynamics is the δf particle in cell (PIC) Monte Carlo code EUTERPE. The Φ considered in the calculations is provided by the neoclassical code GSRAKE and by EUTERPE self-consistently. The results indicate a strong mitigation of the impurity inward flux predicted by the standard mono-energetic neoclassical theory.
Theoretically, a quantitative description of the neoclassical impurity transport is complicated by the breakdown of the assumption of small qΦ/T for impurities, where q is the electric charge, T the temperature in energy units, and Φ the electrostatic potential variation within the flux surface.
The present work describes quantitatively the particle transport of impurities in the frame of local neoclassical theory when qΦ/T = O(1) in the Large Helical Device (LHD) stellarator. The central numerical tool used to describe the impurity dynamics is the δf particle in cell (PIC) Monte Carlo code EUTERPE. The Φ considered in the calculations is provided by the neoclassical code GSRAKE and by EUTERPE self-consistently. The results indicate a strong mitigation of the impurity inward flux predicted by the standard mono-energetic neoclassical theory.
Practical information
- Informed public
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Organizer
- CRPP
Contact
- Prof. P. Ricci