Investigations of the role of nonlinear couplings in structure formation and transport regulation: Experiment, simulation, and theory

In this paper, we report on an integrated program of experimental, computational, and theoretical studies of sheared zonal flows and radially extended convective cells, with the aim of assessing the results of theory-experiment and theory-simulation comparisons. In particular, simulations are used as test beds for verifying analytical predictions (specifically locality and directionality of energy transfer) of nonlinear dynamics and to investigate the suitability of bispectral analysis for studying nonlinear couplings. Initial comparisons to experimental results are presented, and future experimental studies are motivated. We also present analytic and numerical work investigating the role of structures in transport.