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arXiv · 2111.06022

Zonal profile corrugations and staircase formation: Role of the transport crossphase

M. Leconte·T. Kobayashi
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Abstract

Recently, quasi-stationary structures called $E \times B$ staircases were observed in gyrokinetic simulations, in all transport channels [Dif-Pradalier et al. Phys. Rev. Lett. 114, 085004 (2015)]. We present a novel analytical theory - supported by collisional drift-wave fluid simulations - for the generation of density profile corrugations (staircase), independent of the action of zonal flows: Turbulent fluctuations self-organize to generate quasi-stationary radial modulations $\Delta\theta(r,t)$ of the transport crossphase $\theta$ between density and electric potential fluctuations. The radial modulations of the associated particle flux drive zonal corrugations of the density profile, via a modulational instability. In turn, zonal density corrugations regulate the turbulence via nonlinear damping of the fluctuations.

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M. Leconte, T. Kobayashi. 2021-11-11. Zonal profile corrugations and staircase formation: Role of the transport crossphase. https://doi.org/10.1063/5.0030018

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