Zonal density staircase formation in collisional drift-wave turbulence

TL;DR

This paper investigates how zonal density staircases form and influence turbulence suppression in collisional drift-wave turbulence, highlighting the role of the adiabaticity parameter in the dynamics.

Contribution

It demonstrates the impact of the adiabaticity parameter on the effectiveness of zonal density in turbulence suppression through 2D simulations.

Findings

Zonal density corrugations' ability to suppress turbulence decreases with higher adiabaticity.

Zonal flows dominate in the near-adiabatic regime.

Nonlinear transport crossphase shows radial modulations linked to zonal density.

Abstract

Turbulence-driven quasi-stationnary structures known as 'staircase' are investigated using the collisional drift-wave model. Two-dimensional simulations show that the ability of zonal density corrugations to suppress turbulence are affected by the adiabaticity parameter (inversely proportional to collision frequency). As the adiabaticity parameter increases, zonal density becomes less efficient at suppressing turbulence, and zonal flows become dominant in the near-adiabatic regime. The nonlinear transport crossphase displays radial modulations associated to zonal density.