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Enhanced particle transport events approaching the density limit of the J-TEXT tokamak
- Source :
- Nuclear Fusion, vol 61, iss 12
- Publication Year :
- 2021
- Publisher :
- eScholarship, University of California, 2021.
-
Abstract
- Enhanced particle transport events are discovered and analyzed as the density limit of the J-TEXT tokamak is approached. Edge shear layer collapse is observed and the ratio of Reynolds power to turbulence production decreases. Simultaneously, the divergence of turbulence internal energy flux (i.e. turbulence spreading) increases, indicating that shear layer collapse triggers an outward spreading event. Studies of correlations show that the enhanced particle transport events are quasi-coherent, and manifested primarily in density fluctuations which exhibit positive skewness. Electron adiabaticity emerges as the critical parameter which signals transport event onset. For α < 0.35 as density approaches the Greenwald density, both turbulence spreading and density fluctuations rise rapidly. Taken together, these results elucidate the connections between edge shear layer, density fluctuations, particle transport events, turbulence spreading and plasma edge cooling as the density limit is approached.
- Subjects :
- Physics
Nuclear and High Energy Physics
Tokamak
shear flow
Fluids & Plasmas
Molecular
density limit
Condensed Matter Physics
Particle transport
Atomic
law.invention
Nuclear physics
Physics::Fluid Dynamics
turbulence spreading
Particle and Plasma Physics
law
particle transport
Density limit
Nuclear
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Nuclear Fusion, vol 61, iss 12
- Accession number :
- edsair.doi.dedup.....9f4951ce42f1658fa8cc419cb4788e7f