2005/06/01 by Bruce Scott, Bruce D. Scott · 3 citations
Physics and Astronomy · #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research #Solar and Space Plasma Dynamics
paper · doi:10.1063/1.1917866
openalex publication_date 2005/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/05/21
The competition between drift wave and interchange physics in general E-cross-B drift turbulence is studied with computations in three-dimensional tokamak flux tube geometry. For a given set of background scales, the parameter space can be covered by the plasma β and drift wave collisionality. At large enough plasma β the turbulence breaks out into ideal ballooning modes and saturates only by depleting the free energy in the background pressure gradient. At high collisionality it finds a more gradual transition to resistive ballooning. At moderate β and collisionality it retains drift wave character, qualitatively identical to simple two-dimensional slab models. The underlying cause is the nonlinear vorticity advection through which the self-sustained drift wave turbulence supersedes the linear instabilities, scattering their structure apart before they can grow, imposing its own physical character on the dynamics. This vorticity advection catalyses the gradient drive, while saturation occurs solely through turbulent mixing of pressure disturbances. This situation persists in the whole of tokamak edge parameter space. Both simplified isothermal models and complete warm ion models are treated.