Radial Spreading of Drift Wave-Zonal Flow Turbulence via Soliton Formation

TL;DR

This paper investigates the formation and dynamics of soliton structures in drift wave-zonal flow turbulence, showing how they propagate and cause radial spreading, impacting turbulence transport in plasma systems.

Contribution

It introduces a self-consistent model demonstrating soliton formation and their role in turbulence spreading, linking slab and toroidal geometries.

Findings

Solitons propagate at group velocity depending on amplitude

Soliton interactions include generation, destruction, collision, reflection

Radial spreading of turbulence influences transport scaling

Abstract

The self-consistent spatiotemporal evolution of drift wave (DW) radial envelope and zonal flow (ZF) amplitude is investigated in a slab model [1]. Stationary solution of the coupled partial differential equations in a simple limit yields formation of DW-ZF soliton structures, which propagate at group velocity depending on the envelope peak amplitude. Additional interesting physics, e.g. generation, destruction, collision and reflection of solitons, as well as turbulence bursting can also be observed due to effects of linear growth/damping, dissipation, equilibrium nonuniformities and soliton dynamics. The propagation of soliton causes significant radial spreading of DW turbulence and therefore can affect transport scaling with system size by broadening of the turbulent region. Correspondence of the present analysis with the description of DW-ZF interactions in toroidal geometry [2, 3] is also elucidated.