Disturbances in a power transmission system

A simple model for a power transmission system is presented. In this model, disturbances of all sizes may occur. They are randomly triggered and have the characteristic behavior of avalanches. A single parameter describes the scaling of the avalanche size. This parameter combines a measure of closeness to the maximum load, size of transferred loads during an overloading event, and connectivity of the system. The probability distribution function of the size of the disturbance has power-scaling range with the exponent close to -1.

In search of the elusive zonal flow using cross-bicoherence analysis

We show that the modulational instability growth rate of zonal flows is determined directly from the quasilinear wave kinetic equation. We also demonstrate the relation between zonal-flow growth and the cross bispectrum of the high-frequency drift-wave-driven Reynolds stress and the low-frequency plasma potential by explicit calculation. Experimental measurements of the spatiotemporal evolution of the spectrum integrated bicoherence at the L-->H transition near the edge shear layer indicate a modification in the nonlinear phase coupling, which might be linked to the generation of sheared ExB flows.