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In this paper we present scaling of large-scale quantities like Peclét and Nusselt numbers, and the dissipation rates of kinetic energy and entropy. Our arguments are based on the scaling of bulk quantities and earlier experimental and simulation results. We also present the inertial-range properties of spectra and fluxes of kinetic energy and entropy. [ABSTRACT FROM AUTHOR]

Kinetic evolution of the Orszag-Tang vortex is studied using collisionless hybrid simulations based on particle in cell ions and fluid electrons. In magnetohydrodynamics (MHD) this configuration leads rapidly to broadband turbulence. An earlier study [1] estimated the dissipation in the system. A comparison of MHD & hybrid simulations showed similar behavior at large scales but substantial differences at small scales. The hybrid magnetic energy spectrum shows a break at the scale where Hall term in the Ohm’s law becomes important. The protons heat perpendicularly and most of the energy is dissipated through magnetic interactions. Here, the space time structure of the system is studied using frequency-wavenumber (k-ω) decomposition. No clear resonances appear, ruling out the cyclotron resonances as a likely candidate for the perpendicular heating. The only distinguishable wave modes present, which constitute a small percentage of total energy, are magnetosonic modes. [ABSTRACT FROM AUTHOR]

The nonlinear interaction between drift turbulence and zonal flows plays a key role in determining the turbulence amplitude, spatiotemporal scale and subsequent transport and is therefore of significant interest in magnetic fusion research. We summarize multipoint time-domain probe studies, frequency-domain studies, and direct visualization studies of this important process. The fluctuation-induced Reynolds stress is shown to be consistent with the observed shear flow; spatially resolved direct measurement of nonlinear exchange of energy between drift fluctuations and zonal flows and direct imaging show how the drift instability generates isotropic vortex structures which then propagate outwards towards the zonal flow shear layer, where they are stretched and thinned, and then incorporated into the shear layer, thereby maintaining it against damping mechanisms. The drift fluctuation-zonal flow nonlinear interactions, shearing rate, and cross-field transport are consistent with a critical gradient transport model. [ABSTRACT FROM AUTHOR]

Recent work on second sound acoustic turbulence in superfluid 4He is reviewed. Observations of forward and inverse energy cascades are described. The onset of the inverse cascade occurs above a critical driving energy and it is accompanied by giant waves that constitute an acoustic analogue of the rogue waves that occasionally appear on the surface of the ocean. The theory of the phenomenon is outlined and shown to be in good agreement with the experiments. [ABSTRACT FROM AUTHOR]