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A model for ICRH induced flows in the presence of a strong magnetic field is presented. These flows are the finite temperature counterpart of flows existing in cold plasmas described e.g. in [D. Van Eester et al., Plasma Phys. Control.…

Plasma Physics · Physics 2014-03-20 Dirk Van Eester , Kristel Crombé , Yevgen Kazakov

Planetary magnetic fields are generated by motions of electrically conducting fluids in their interiors. The dynamo problem has thus received much attention in spherical geometries, even though planetary bodies are non-spherical. To go…

Earth and Planetary Astrophysics · Physics 2021-09-09 Jérémie Vidal , David Cébron

The existence of global-in-time classical solutions to the Cauchy problem of compressible magnetohydrodynamic flows with zero magnetic diffusivity is considered in two dimensions. The linear structure is a degenerated hyperbolic-parabolic…

Analysis of PDEs · Mathematics 2014-05-05 Xianpeng Hu

We study kinetic models for traffic flow characterized by the property of producing backward propagating waves. These waves may be identified with the phenomenon of stop-and-go waves typically observed on highways. In particular, a refined…

Analysis of PDEs · Mathematics 2020-02-10 M. Herty , G. Puppo , G. Visconti

The small-scale dynamo provides a highly efficient mechanism for the conversion of turbulent into magnetic energy. In astrophysical environments, such turbulence often occurs at high Mach numbers, implying steep slopes in the turbulent…

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

We study the dynamics of magnetic fields in chiral magnetohydrodynamics, which takes into account the effects of an additional electric current related to the chiral magnetic effect in high energy plasmas. We perform direct numerical…

Plasma Physics · Physics 2022-02-15 Jennifer Schober , Igor Rogachevskii , Axel Brandenburg

Fluctuation dynamos are generic to astrophysical systems. The only analytical model of the fluctuation dynamo is Kazantsev model which assumes a delta-correlated in time velocity field. We derive a generalized model of fluctuation dynamo…

Plasma Physics · Physics 2014-08-25 Pallavi Bhat , Kandaswamy Subramanian

Small-scale dynamo action is often held responsible for the generation of quiet-Sun magnetic fields. We aim to determine the excitation conditions and saturation level of small-scale dynamos in non-rotating turbulent convection at low…

Solar and Stellar Astrophysics · Physics 2018-06-06 Petri J. Käpylä , Maarit J. Käpylä , Axel Brandenburg

We introduce six families of three-dimensional space-periodic steady solenoidal flows, whose kinetic helicity density is zero at any point. Four families are analytically defined. Flows in four families have zero helicity spectrum. Sample…

Fluid Dynamics · Physics 2018-04-06 A. Rasskazov , R. Chertovskih , V. Zheligovsky

Recent experiments have shown that it is possible to study a fundamental astrophysical process such as dynamo action in controlled laboratory conditions using simple MHD flows. In this paper we explore the possibility that Taylor-Couette…

Astrophysics · Physics 2009-11-07 Ashley P. Willis , Carlo F. Barenghi

Chicone et al [Comm Math Phys (1997)] investigated existence of fast dynamos by analyzing the spectrum kinematic magnetic dynamo. In real non-degenerate branch of the spectrum, the kinematic dynamo operator lies on a compact Riemannian 2D…

Cosmology and Nongalactic Astrophysics · Physics 2010-02-10 Garcia de Andrade

We investigate numerically the self-sustained dynamo action in a spinning sphere whose sense of rotation reverses periodically. This system serves as a simple model of a dynamo in small bodies powered by frequent collisions. It is found…

Geophysics · Physics 2015-06-18 Xing Wei , Rainer Arlt , Andreas Tilgner

Stellar radiative zones are typically assumed to be motionless in standard models of stellar structure but there is sound theoretical and observational evidence that this cannot be the case. We investigate by direct numerical simulations a…

Fluid Dynamics · Physics 2018-07-18 Radostin D. Simitev , Friedrich H. Busse

Magnetic fields are a dynamically important component of the turbulent interstellar medium (ISM) of star-forming galaxies. These magnetic fields are due to a dynamo action, which is a process of converting turbulent kinetic energy to…

Astrophysics of Galaxies · Physics 2022-06-01 Amit Seta , Christoph Federrath

We investigate the energy pathways between the velocity and the magnetic fields in a rotating plane layer dynamo driven by Rayleigh-B\'enard convection using direct numerical simulations. The kinetic and magnetic energies are divided into…

Fluid Dynamics · Physics 2022-12-20 Souvik Naskar , Anikesh Pal

The project A2 of the LIMTECH Alliance aimed at a better understanding of those magnetohydrodynamic instabilities that are relevant for the generation and the action of cosmic magnetic fields. These comprise the hydromagnetic dynamo effect…

For a long time, ballooning instabilities have been believed to be a possible triggering mechanism for the onset of substorm and current disruption initiation in the near-Earth magnetotail. Yet the stability of the kinetic ballooning mode…

Plasma Physics · Physics 2020-10-28 Abdullah Khan , Ping Zhu , Rui Han , Ahmad Ali

The project DRESDYN (DREsden Sodium facility for DYNamo and thermohydraulic studies) conducted at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) provides a new platform for a variety of liquid sodium experiments devoted to problems of geo- and…

Fluid Dynamics · Physics 2019-05-22 Andre Giesecke , Tobias Vogt , Thomas Gundrum , Frank Stefani

Context: Convectively-driven flows play a crucial role in the dynamo processes that are responsible for producing magnetic activity in stars and planets. It is still not fully understood why many astrophysical magnetic fields have a…

Solar and Stellar Astrophysics · Physics 2018-05-09 P. J. Bushby , P. J. Käpylä , Y. Masada , A. Brandenburg , B. Favier , C. Guervilly , M. J. Käpylä

We study a two-dimensional motion of a charged particle in a weak random potential and a perpendicular magnetic field. The correlation length of the potential is assumed to be much larger than the de Broglie wavelength. Under such…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 M. M. Fogler , A. Yu. Dobin , V. I. Perel , B. I. Shklovskii