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We consider the backreaction of the magnetic field on the magnetic dynamo coefficients and the role of boundary conditions in interpreting whether numerical evidence for suppression is dynamical. If a uniform field in a periodic box serves…

Astrophysics · Physics 2009-10-31 Eric G. Blackman , George B. Field

We perform numerical experiments to study the shear dynamo problem where we look for the growth of large--scale magnetic field due to non--helical stirring at small scales in a background linear shear flow, in previously unexplored…

Astrophysics of Galaxies · Physics 2015-09-16 Nishant K. Singh , Naveen Jingade

We investigate three-dimensional magnetohydrodynamics turbulence in the presence of both a large-scale velocity and non-uniform magnetic field. By assuming a turbulence driven by an external forcing with both helical and non-helical…

Fluid Dynamics · Physics 2015-05-13 Nicolas Leprovost , Eun-Jin Kim

A rigorous theory for the generation of a large-scale magnetic field by random non-helically forced motions of a conducting fluid combined with a linear shear is presented in the analytically tractable limit of low Rm and weak shear. The…

Astrophysics · Physics 2011-12-15 T. Heinemann , J. C. McWilliams , A. A. Schekochihin

The feasibility of a mean-field dynamo in nonhelical turbulence with superimposed linear shear is studied numerically in elongated shearing boxes. Exponential growth of magnetic field at scales much larger than the outer scale of the…

For more than a decade, the so-called shearing box model has been used to study the fundamental local dynamics of accretion discs. This approach has proved to be very useful because it allows high resolution and long term studies to be…

Astrophysics · Physics 2009-11-13 L. J. Silvers

Motivated by a number of recent experimental and computational studies of the dynamics of fluids plunged in quenched-disordered external fields, we report on a theoretical investigation of this topic within the framework of the…

Soft Condensed Matter · Physics 2018-10-05 Thomas Konincks , Vincent Krakoviack

Nonlinear mean-field models of the solar dynamo show long-term variability, which may be relevant to different states of activity inferred from long-term radiocarbon data. This paper is aimed to probe the dynamo hysteresis predicted by the…

Solar and Stellar Astrophysics · Physics 2015-04-24 Bidya Binay Karak , Leonid L. Kitchatinov , Axel Brandenburg

Thouless pumps are time-periodic one-dimensional systems that capture the physics of the two-dimensional quantum Hall effect via the quantized pumping of particles under adiabatic modulation. Recent work in photonics has shown that…

Pattern Formation and Solitons · Physics 2025-02-21 Marius Jürgensen , Mikael C. Rechtsman

The emergence of tilted bipolar active regions and the dispersal of their flux, mediated via processes such as diffusion, differential rotation and meridional circulation is believed to be responsible for the reversal of the Sun's polar…

Solar and Stellar Astrophysics · Physics 2010-09-28 Andrés Muñoz-Jaramillo , Dibyendu Nandy , Petrus C. H. Martens , Anthony R. Yeates

Predictions of solar cycle 24 obtained from advection-dominated and diffusion-dominated kinematic dynamo models are different if the Babcock-Leighton mechanism is the only source of the poloidal field. Yeates et al. (2008) argue that the…

Solar and Stellar Astrophysics · Physics 2020-10-07 Soumitra Hazra , Allan Sacha Brun , Dibyendu Nandy

We study a simple model for the solar dynamo in the framework of the Parker migratory dynamo, with a nonlinear dynamo saturation mechanism based on magnetic helicity conservation arguments. We find a parameter range in which the model…

Astrophysics · Physics 2009-11-07 N. Kleeorin , K. Kuzanyan , D. Moss , I. Rogachevskii , D. Sokoloff , H. Zhang

The temporal variation of the horizontal velocity in subsurface layers beneath three different types of active regions is studied using the technique of ring diagrams. In this study, we select active regions (ARs) 10923, 10930, 10935 from…

Solar and Stellar Astrophysics · Physics 2015-06-05 K. Jain , R. W. Komm , I González Hernández , S. C. Tripathy , F. Hill

This work is motivated by mathematical questions arising in differential equation models for autocatalytic reactions. In particular, this paper answers an open question posed by Guckenheimer and Scheper [SIAM J. Appl. Dyn. Syst. 10-1…

Dynamical Systems · Mathematics 2015-03-06 Christian Kuehn

In this work, we investigate the dynamics of a non-local model describing spontaneous cell polarisation. It consists in a drift-diffusion equation set in the half-space, with the coupling involving the trace value on the boundary. We…

Analysis of PDEs · Mathematics 2011-05-24 Vincent Calvez , Rhoda Hawkins , Nicolas Meunier , Raphael Voituriez

We introduce on/off intermittency into a mean field dynamo model by imposing stochastic fluctuations in either the alpha effect or through the inclusion of a fluctuating electromotive force. Sufficiently strong small scale fluctuations with…

Astrophysics · Physics 2008-03-27 A. Brandenburg , E. A. Spiegel

The impact of leading collective electronic fluctuations on a free energy of a prototype 1D model for molecular systems is considered within the recently developed Fluctuating Local Field (FLF) approach. The FLF method is a non-perturbative…

Strongly Correlated Electrons · Physics 2022-01-14 Yana S. Lyakhova , Evgeny A. Stepanov , Alexey N. Rubtsov

Using a Luttinger liquid theory we investigate the time evolution of the particle density of a one-dimensional fermionic system with open boundaries and subject to a finite duration quench of the inter-particle interaction. We provide…

Strongly Correlated Electrons · Physics 2016-08-16 S. Porta , F. M. Gambetta , F. Cavaliere , N. Traverso Ziani , M. Sassetti

Results are presented for the phase separation process of a binary mixture subject to an uniform shear flow quenched from a disordered to a homogeneous ordered phase. The kinetics of the process is described in the context of the…

Condensed Matter · Physics 2012-04-05 F. Corberi , G. Gonnella , A. Lamura

The linear and renormalized nonlinear kinetic theory of drift instability of plasma shear flow across the magnetic field, which has the Kelvin's method of shearing modes or so-called non-modal approach as its foundation, is developed. The…

Plasma Physics · Physics 2015-05-27 V. S. Mikhailenko , V. V. Mikhailenko , K. N. Stepanov