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Flux-driven simulations of turbulence collapse.
- Source :
-
Physics of Plasmas . 2015, Vol. 22 Issue 3, p1-5. 5p. 6 Graphs. - Publication Year :
- 2015
-
Abstract
- Using three-dimensional nonlinear simulations of tokamak turbulence, we show that an edge transport barrier (ETB) forms naturally once input power exceeds a threshold value. Profiles, turbulence-driven flows, and neoclassical coefficients are evolved self-consistently. A slow power ramp-up simulation shows that ETB transition is triggered by the turbulence-driven flows via an intermediate phase which involves coherent oscillation of turbulence intensity and E×B flow shear. A novel observation of the evolution is that the turbulence collapses and the ETB transition begins when RT > 1 at t = tR (RT: normalized Reynolds power), while the conventional transition criterion (ωE×B>γlin where ωE×B denotes mean flow shear) is satisfied only after t = tC (>tR), when the mean flow shear grows due to positive feedback. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 1070664X
- Volume :
- 22
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Physics of Plasmas
- Publication Type :
- Academic Journal
- Accession number :
- 101902279
- Full Text :
- https://doi.org/10.1063/1.4914841