Collisionality driven turbulent particle transport changes in DIII-D H-mode plasmas
Artikel i vetenskaplig tidskrift, 2020

The results of the experimental dimensionless scan in this paper confirm that there is an increase in density peaking towards lower collisionality and that this can be partly linked to a shift in the turbulence regime from ITG towards TEM. However at the lowest collisionality, the changes in turbulence and transport are much more pronounced than expected from direct collisionality effect on the turbulence. In this paper, the collisionality, ν ∗ is varied by a factor 5, while keeping ρ ∗, q, β, M, fixed. Additionally, a 3 Hz gas puff modulation is applied to modulate the electron density profile and extract the perturbed transport coefficients using two diagnostics. The transport analysis shows that the increase in density peaking at low ν ∗ is linked to an increase in the inward particle pinch and not an increase in core fueling. These observations are not only in agreement with prior modeling scans of how turbulence changes as a function of collisionality and its impact upon the particle fluxes, but also with the multi-machine database (Fable E. et al 2010 Plasma Phys. Control. Fusion 52 015007) (Angioni C. et al 2003 Phys. Rev. Lett. 90 205003). The changes in turbulence across the collisionality scan were captured at large scale by the BES and at smaller scale by the DBS. A comparison with gradient-driven GENE simulations showed similar trends at both scales. Moreover, the changes observed in overall transport are in agreement with gradient-driven TGLF particle flux simulations. This indicates that TGLF/GENE when given the gradients as input, are able to reproduce the experimentally observed turbulence changes.






S. Mordijck

College of William and Mary

T. L. Rhodes

University of California

L. Zeng

University of California

A. Salmi

Teknologian Tutkimuskeskus (VTT)

T. Tala

Teknologian Tutkimuskeskus (VTT)

C. C. Petty

General Atomics

G. R. McKee

University of Wisconsin Madison

R. Reksoatmodjo

College of William and Mary

Frida Eriksson

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Emil Fransson

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Hans Nordman

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Nuclear Fusion

0029-5515 (ISSN) 1741-4326 (eISSN)

Vol. 60 6 066019


Fusion, plasma och rymdfysik



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