For the purpose of meeting the requirement for image chromatic information storage, data processing and transmission in turbulence precise detection, this paper presents a new data optimization method of turbulence image chromatic data based on energy optimization surface construction and multi-order Random Sample Consensus (RANSAC) estimation. Though extracting turbulence image’s chromatic dat...

We discuss several improvements in the detection of atmospheric turbulence using SLOpe Detection And Ranging (SLODAR). Frequently, SLODAR observations have shown strong ground-layer turbulence, which is beneficial to adaptive optics. We show that current methods which neglect atmospheric propagation effects can underestimate the strength of high altitude turbulence by up to ~ 30%. We show that ...

Turbulence in a superfluid in the zero-temperature limit consists of a dynamic tangle of quantized vortex filaments. Different types of turbulence are possible depending on the level of correlations in the orientation of vortex lines. We provide an overview of turbulence in superfluid (4)He with a particular focus on recent experiments probing the decay of turbulence in the zero-temperature reg...

MHD turbulence plays a central role in the physics of star-forming molecular clouds and the interstellar medium. I here show that MHD turbulence in molecular clouds must be driven to account for the observed supersonic motions in the clouds, as even strongly magnetized turbulence decays quickly. I then show that driven MHD turbulence can globally support gravitationally unstable regions, but lo...

Magnetohydrodynamic (MHD) turbulence is pervasive in astrophysical systems. Recent highresolution numerical simulations suggest that the energy spectrum of strong incompressible MHD turbulence is E(k⊥) ∝ k ⊥ . So far, there has been no phenomenological theory that simultaneously explains this spectrum and satisfies the exact analytic relations for MHD turbulence due to Politano & Pouquet. Indee...

In this work, statistical properties of compressible hydrodynamic and magnetohydrodynamic turbulence are studied using direct numerical simulations. The properties of turbulent flows change when average flow velocities within the turbulence exceed the speed of sound in the medium. High flow velocities lead to the formation of shocks, and some of the base assumptions of turbulence theories of in...

We analyze 3D numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We find that the time scale for the energy cascade is consistent with the Goldreich-Sridhar model of strong MHD turbulence. Using higher order longitudinal structure functions we show that the turbulent motions in the plane ...

Recently found unstable time-periodic solutions to the incompressible Navier-Stokes equation are reviewed to discuss their relevance to plane Couette turbulence and isotropic turbulence. It is shown that the periodic motion embedded in the Couette turbulence exhibits a regeneration cycle of near-wall coherent structures, which consists of formation and breakdown of streamwise vortices and low-v...

The spherical torus edge region is among the most challenging regimes for plasma turbulence simulations. Here, we measure the spatial and temporal properties of ion-scale turbulence in the steep gradient region of H-mode pedestals during edge localized mode-free, MHD quiescent periods in the National Spherical Torus Experiment. Poloidal correlation lengths are about 10 qi, and decorrelation tim...

Stochastic Structural Stability Theory (SSST) provides an autonomous, deterministic, nonlinear dynamical system for evolving a turbulent mean state. In this work SSST is applied to the problem of understanding the origin and dynamics of roll/streak structures associated with both transition to turbulence and maintenance of the turbulent state. Roll structures in the cross-stream/spanwise plane ...