Multi-field turbulence and transport barrier measurements and validation of predictive codes for high-performance, negative triangularity ELM-free DIII-D plasmas

Le résumé fourni par la source

Abstract A recent DIII-D campaign demonstrated high confinement, edge-localized mode-free plasmas in strongly shaped, diverted negative triangularity (NT) configurations. This paper presents new multi-field turbulence and flow measurements near the edge to understand the physics of edge transport of these plasmas. Correlation electron cyclotron emission and Doppler backscattering measurements provide electron-temperature fluctuation levels, density-fluctuation levels, radial correlation lengths, and poloidal turbulence velocity profiles. The measurements show a modest edge electron temperature/pressure pedestal, a localized poloidal-velocity well near the pedestal-top region, and the peaking of both temperature and density fluctuation levels near the region of minimum poloidal velocity shear, consistent with edge-transport-barrier formation. Linear trapped gyro-landau fluid calculations indicate a transition from predominantly ITG-like modes in the inner region to TEM-like modes near the pedestal top, approximately coincident with the observed increase in fluctuation levels. These results provide new quantitative constraints for testing predictive models of turbulence and transport in high-performance NT tokamak plasmas.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.