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Related papers: Influence of turbulence on the dynamo threshold

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We present local numerical models of accretion disk turbulence driven by the magnetorotational instability with varying shear rate. The resulting turbulent stresses are compared with predictions of a closure model in which triple…

Astrophysics · Physics 2009-01-17 A. J. Liljeström , M. J. Korpi , P. J. Käpylä , A. Brandenburg , W. Lyra

We investigate the effect of turbulence on the collisional growth of um-sized droplets through high- resolution numerical simulations with well resolved Kolmogorov scales, assuming a collision and coalescence efficiency of unity. The…

Atmospheric and Oceanic Physics · Physics 2019-01-14 Xiang-Yu Li , A. Brandenburg , G. Svensson , N. E. L. Haugen , B. Mehlig , I. Rogachevskii

We review the results obtained by three successful fluid dynamo experiments and discuss what has been learnt from them about the effect of turbulence on the dynamo threshold and saturation. We then discuss several questions that are still…

Fluid Dynamics · Physics 2009-11-13 F. Petrelis , N. Mordant , S. Fauve

A reduction of total mean turbulent pressure due to the presence of magnetic fields was previously shown to be a measurable effect in direct numerical simulations. However, in the studied parameter regime the formation of large-scale…

Solar and Stellar Astrophysics · Physics 2012-04-09 Koen Kemel , Axel Brandenburg , Nathan Kleeorin , Igor Rogachevskii

We re-examine the nature of the turbulent magnetic diffusivity tensor of mean field electrodynamics and show that an inconsistency arises if it is calculated via consideration of time-independent magnetic fields. Specifically, the predicted…

Solar and Stellar Astrophysics · Physics 2010-01-14 David W. Hughes , Michael R. E. Proctor

The role of shear in alleviating catastrophic quenching by shedding small-scale magnetic helicity through fluxes along contours of constant shear is discussed. The level of quenching of the dynamo effect depends on the quenched value of the…

Astrophysics · Physics 2008-08-08 Axel Brandenburg

Many systems respond to slowly changing external conditions with crackling noise, created by avalanches or pulses of a broad range of sizes. Examples range from Barkhausen Noise in magnets to earthquakes. Here we discuss how the scaling…

Disordered Systems and Neural Networks · Physics 2009-11-07 R. A. White , K. A. Dahmen

This article presents a calculation of the mean electromotive force arising from general small-scale magnetohydrodynamical turbulence, within the framework of the second-order correlation approximation. With the goal of improving…

High Energy Astrophysical Phenomena · Physics 2015-11-23 Jonathan Squire , Amitava Bhattacharjee

Many astrophysical systems encompass very large dynamical ranges in space and time, which are not accessible by direct numerical simulations. Thus, idealized subvolumes are often used to study small-scale effects including the dynamics of…

Fluid Dynamics · Physics 2018-05-23 Philipp Grete , Brian W. O'Shea , Kris Beckwith

Lean turbulent premixed hydrogen/air flames have substantially increased flame speeds, commonly attributed to differential diffusion effects. In this work, the effect of turbulence on lean hydrogen combustion is studied through Direct…

Fluid Dynamics · Physics 2024-08-20 Matthew X. Yao , Guillaume Blanquart

(Abridged) The small-scale dynamo may play a substantial role in magnetizing the Universe under a large range of conditions, including subsonic turbulence at low Mach numbers, highly supersonic turbulence at high Mach numbers and a large…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Dominik R. G. Schleicher , Jennifer Schober , Christoph Federrath , Stefano Bovino , Wolfram Schmidt

Surface roughness significantly impacts transition to turbulence, especially over high-speed, blunt geometries where surface ablation is necessary to mitigate heat loads during atmospheric entry. Inspired by sand-grain roughness experiments…

Fluid Dynamics · Physics 2026-02-04 Sean Dungan , Mateus Braga , Robyn Macdonald , Christoph Brehm

Within the framework of one-dimensional Laval-Dubrulle-Nazarenko type model for the Lagrangian acceleration in developed turbulence studied in the work [A.K. Aringazin and M.I. Mazhitov, cond-mat/0305186] we focus on the effect of…

Statistical Mechanics · Physics 2007-05-23 A. K. Aringazin

The effects of noise on the dynamics of nonlinear systems is known to lead to many counter-intuitive behaviors. Using simple planar limit cycle oscillators, we show that the addition of moderate noise leads to qualitatively different…

Chaotic Dynamics · Physics 2015-06-17 Jay M. Newby , Michael A. Schwemmer

We analyze the effects of noise on the traveling wave dynamics in neural fields. The noise influences the dynamics on two scales: first, it causes fluctuations in the wave profile, and second, it causes a random shift in the phase of the…

Probability · Mathematics 2015-08-06 Eva Lang

Magnetohydrodynamic turbulence and magnetic reconnection are ubiquitous in astrophysical environments. In most situations, these processes do not occur in isolation, but interact with each other. This renders a comprehensive theory of these…

Plasma Physics · Physics 2018-03-29 L. Comisso , Y. -M. Huang , M. Lingam , E. Hirvijoki , A. Bhattacharjee

We introduce a stochastic version of Proudman-Taylor model, a 2D-3C fluid approximation of the 3D Navier-Stokes equations, with the small-scale turbulence modeled by a transport-stretching noise. For this model we may rigorously take a…

Probability · Mathematics 2024-06-12 Franco Flandoli , Dejun Luo

The effect of transport noise on a 2D fluid may depend on the space-scale of the noise. We investigate numerically the dissipation properties of very small-scale transport noise. As a test problem we consider the Kelvin-Helmholtz…

Fluid Dynamics · Physics 2024-01-08 Franco Flandoli , Silvia Morlacchi , Andrea Papini

We study the impact of stochastic perturbations to deterministic dynamical systems using the formalism of the Ruelle response theory and explore how stochastic noise can be used to explore the properties of the underlying deterministic…

Statistical Mechanics · Physics 2015-05-27 Valerio Lucarini

We analyze the effects of noise on the permutation entropy of dynamical systems. We take as numerical examples the logistic map and the R\"ossler system. Upon varying the noise strengthfaster, we find a transition from an…

Data Analysis, Statistics and Probability · Physics 2015-09-30 C. Quintero-Quiroz , Simone Pigolotti , M. C. Torrent , Cristina Masoller