Essay On Parallel Flow Shear

1138 Words5 Pages
In this work, we discussed the role of parallel flow shear in controlling the secondary pattern selection problem in drift wave turbulence. The principal results of this paper are summarized as follows. (-- removed HTML --) (-- removed HTML --) (-- removed HTML --) 1. (-- removed HTML --) (-- removed HTML --) The generation of zonal flows and streamers is formulated within the modulational instability framework. The effect of parallel flow shear has been included. The overall dynamics is governed by nonlinear Schrödinger equations, both for streamers and for zonal flows. The effect of parallel flows enters both diffraction and self-focusing terms. (-- removed HTML --) (-- removed HTML --) (-- removed HTML --) (-- removed HTML…show more content…
First, we have considered only stable drift waves with parallel flow shear, or a saturated parallel velocity gradient mode. The unstable, active case is not considered. In this case, as discussed for the case of fluid Rayleigh-Benard convection, (-- removed HTML --) (-- removed HTML --) 32 (-- removed HTML --) (-- removed HTML --) we would need an analysis based on the complex Ginzburg-Landau equation. Secondly, we used a simplified fluid model for analytical simplicity. However, as we approach the marginal value for PVG instability, kinetic effects, such as the finite Larmor radius effect and ion Landau-damping, may enter. Third, non-adiabatic electrons can be relevant. This is because the mode becomes unstable and a finite particle flux arises. Particle transport relaxes the density profile, which effectively increases the Mach number (-- removed HTML --) (-- removed HTML --) (-- removed HTML --) (-- removed HTML --) M (-- removed HTML --) (-- removed HTML --) = (-- removed HTML --) (-- removed HTML --) | (-- removed HTML --) (-- removed HTML --) 〈 (-- removed HTML --) (-- removed HTML --) (-- removed HTML --) v (-- removed HTML --) (-- removed HTML --) ∥ (-- removed HTML --) (-- removed HTML --) (-- removed HTML --) 〉 (-- removed HTML --) (-- removed HTML --) ′ (-- removed HTML --) (-- removed HTML --) / (-- removed HTML --) (-- removed HTML
Get Access