Aspects of flow generation and saturation in drift-wave turbulence

Elasticity in drift-wave-zonal-flow turbulence.

We present a theory of turbulent elasticity, a property of drift-wave-zonal-flow (DW-ZF) turbulence, which follows from the time delay in the response of DWs to ZF shears. An emergent dimensionless parameter |〈v〉'|/Δωk is found to be a measure of the degree of Fickian flux-gradient relation breaking, where |〈v〉'| is the ZF shearing rate and Δωk is the turbulence decorrelation rate. For |〈v〉'|/Δ...

Onset of Turbulence in a Drift Wave–Zonal Flow System

Numerical analyses of bifurcation phenomena in the Hasegawa-Wakatani 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 tur...

Resistive drift-wave turbulence

Two-dimensional resistive drift-wave turbulence is studied by high-resolution numerical simulations in the Iimit of small viscosity. Density and potential fluctuations are cross-coupled by resistive dissipation, proportional to the adiabaticity parameter, F, which determines the character of the system: adiabatic (ml) or hydrodynamic (Z% 1). Various cases are computed for 0. I ~%<5. Energy spec...

Coherent structure phenomena in drift wave-zonal flow turbulence

Zonal flows are azimuthally symmetric plasma potential perturbations spontaneously generated from small-scale drift-wave fluctuations via the action of Reynolds stresses. We show that, after initial linear growth, zonal flows can undergo further nonlinear evolution leading to the formation of long-lived coherent structures which consist of self-bound wave packets supporting stationary shear lay...

Small scale coherent vortex generation in drift wave-zonal flow turbulence