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We study local power fluctuations in numerical simulations of stationary, homogeneous, isotropic turbulence in two and three dimensions with Gaussian forcing. Due to the near-Gaussianity of the one-point velocity distribution, the…

Statistical Mechanics · Physics 2009-11-13 M. M. Bandi , Sergei G. Chumakov , Colm Connaughton

The flux lines dynamics have been investigated on MgB2 bulk superconductors obtained by reactive liquid infiltration by measuring the ac magnetic susceptibility. The fundamental and third harmonics have been studied as a function of…

Superconductivity · Physics 2009-11-07 C. Senatore , M. Polichetti , D. Zola , T. Di Matteo , G. Giunchi , S. Pace

Superfluidity is a fascinating phenomenon that, at the macroscopic scale, leads to dissipationless flow and the emergence of vortices. While these macroscopic manifestations of superfluidity are well described by theories that have their…

Quantum Gases · Physics 2014-06-18 Yangqian Yan , D. Blume

In Ref. [1] the statistical structure of the turbulent cascade in the context of non-additive entropy was considered. Here we suggest that the vortex line ensemble in the Vinen quantum turbulence in superfluids is described by the…

Statistical Mechanics · Physics 2026-04-28 G. E. Volovik

The elementary structures of turbulence, i.e., vortex tubes, are studied using velocity data obtained in laboratory experiments for boundary layers and duct flows at microscale Reynolds numbers 332-1934. While past experimental studies…

Fluid Dynamics · Physics 2009-11-13 H. Mouri , A. Hori

In superfluid helium, vorticity is quantized and constrained on line-like phase singularities, called quantum or quantized vortices. By visualizing the motion of sub-micron frozen particles in superfluid $^{4}$He, we directly observe for…

We perform three-dimensional (3D) compressible MHD simulations over many dynamical times for an extended range of sonic and Alfven Mach numbers and analyze the statistics of 3D density and 2D column density, which include probability…

Astrophysics · Physics 2009-01-19 G. Kowal , A. Lazarian , A. Beresnyak

Intermittent fluctuations in the boundary of magnetically confined plasmas are investigated by numerical turbulence simulations of a reduced fluid model describing the evolution of the plasma density and electric drift vorticity in the…

We use the plasma density based on measurements of the probe-to-spacecraft potential in combination with magnetic field measurements by MAG to study fields and density fluctuations in the solar wind observed by Solar Orbiter during the…

The local density of states of a degenerate semiconductor is investigated at low magnetic fields. In order to realize this experiment, we designed a strongly asymmetric double-barrier heterostructure with heavily doped contacts and study…

Condensed Matter · Physics 2009-10-28 T. Schmidt , R. J. Haug , V. I. Fal'ko , K. v. Klitzing , A. Foerster , H. Lueth

The flow of superfluid $^4$He around a translationally oscillating sphere, levitating without mechanical support, can either be laminar or turbulent, depending on the velocity amplitude. Below a critical velocity $v_c$ that scales as…

Other Condensed Matter · Physics 2017-11-17 Michael Niemetz , Risto Hänninen , Wilfried Schoepe

This paper addresses the problem of vortex formation during a rapid quench in a superconducting film. It builds on previous work showing that in a local gauge theory there are two distinct mechanisms of defect formation, based on…

Condensed Matter · Physics 2007-05-23 T. W. B. Kibble , A. Rajantie

We calculate suppression of inter- and intralayer superconducting currents due to equilibrium phase fluctuations and find that, in contrast to a recent prediction, the effect of thermal fluctuations cannot account for linear temperature…

Superconductivity · Physics 2009-10-31 S. N. Artemenko , S. V. Remizov

Vertically 0.042-m-spaced moored high-resolution temperature sensors are used for detailed internal wave-turbulence monitoring near Texel North Sea and Wadden Sea beaches on calm summer days. In the maximum 2 m deep waters irregular…

Atmospheric and Oceanic Physics · Physics 2019-06-07 Hans van Haren

We study turbulent flows in pressure-driven ducts with square cross-section through direct numerical simulation in a wide enough range of Reynolds number to reach flow conditions which are representative of fully developed turbulence.…

Fluid Dynamics · Physics 2018-03-14 S. Pirozzoli , D. Modesti , P. Orlandi , F. Grasso

The statistics of the field structure in the vortex core surrounding phase singularities in random wave fields are measured and calculated for diffusive and localized waves. Excellent agreement is found between experiment and theory. The…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Sheng Zhang , Azriel Z Genack

We discuss a new technique for studying astrophysical turbulence that utilizes the statistics of Doppler-broadened spectral lines. The technique relates the power Velocity Coordinate Spectrum (VCS), i.e. the spectrum of fluctuations…

Astrophysics · Physics 2009-11-11 A. Lazarian , D. Pogosyan

The flux noise spectrum and complex impedance for a 500 {\AA} thick YBCO film are measured and compared with predictions for two dimensional vortex fluctuations. It is verified that the complex impedance and the flux noise spectra are…

We theoretically explore key concepts of two-dimensional turbulence in a homogeneous compressible superfluid described by a dissipative two-dimensional Gross-Pitaeveskii equation. Such a fluid supports quantized vortices that have a size…

Quantum Gases · Physics 2012-10-11 Ashton S. Bradley , Brian P. Anderson

Historically, there is little faith in particle tracking velocimetry (PTV) as a tool to make quantitative measurements of thermal counterflow in He II, since tracer particle motion is complicated by influences from the normal fluid,…

Other Condensed Matter · Physics 2019-02-13 Brian Mastracci , Wei Guo