2007/08/31 by Ryusuke Numata, Rowena Ball, R. L. Dewar +1 · 2 citations
Physics and Astronomy · #Ionosphere and magnetosphere dynamics #Laser-Plasma Interactions and Diagnostics #Magnetic confinement fusion research #physics.plasm-ph
paper · pdf · doi:10.1063/1.2796106
published as Phys. Plasmas 14, 102312-1--8 (2007) · 21 pages, 11 figures
arxiv created 2007/08/31 · openalex publication_date 2007/10/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Hasegawa-Wakatani equations, coupling plasma density, and electrostatic potential through an approximation to the physics of parallel electron motions, are a simple model that describes resistive drift wave turbulence. Numerical analyses of bifurcation phenomena in the model are presented, that provide new insights into the interactions between turbulence and zonal flows in the tokamak plasma edge region. The simulation results show a regime where, after an initial transient, drift wave turbulence is suppressed through zonal flow generation. As a parameter controlling the strength of the turbulence is tuned, this zonal-flow-dominated state is rapidly destroyed and a turbulence-dominated state re-emerges. The transition is explained in terms of the Kelvin-Helmholtz stability of zonal flows. This is the first observation of an upshift of turbulence onset in the resistive drift wave system, which is analogous to the well-known Dimits shift in turbulence driven by ion temperature gradients.