English
Related papers

Related papers: Active region formation through the negative effec…

200 papers

We investigate an efficient mechanism for generating magnetic fields in turbulent, collisionless plasmas. By using fully kinetic, particle-in-cell simulations of an initially non-magnetized plasma, we inspect the genesis of magnetization,…

Plasma Physics · Physics 2021-12-01 F. Pucci , M. Viviani , F. Valentini , G. Lapenta , W. H. Matthaeus , S. Servidio

The inner regions of protoplanetary discs, which encompass the putative habitable zone, are dynamically complex, featuring a well-ionised, turbulent active inner region and a poorly ionised `dead' outer region. In this first paper, we…

Earth and Planetary Astrophysics · Physics 2025-12-05 Matthew J. O. Roberts , Henrik N. Latter , Geoffroy Lesur

We studied the developing conditions of sigmoid structure under the influence of magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vector magnetic field measurements from Helioseismic Magnetic…

Solar and Stellar Astrophysics · Physics 2016-09-28 P. Vemareddy , X. Cheng , B. Ravindra

Active regions are open wounds in the Sun's surface. Seismic oscillations from the interior pass through them into the atmosphere, changing their nature in the process to fast and slow magneto-acoustic waves. The fast waves then partially…

Solar and Stellar Astrophysics · Physics 2013-09-12 Paul S. Cally , Hamed Moradi

The saturation mechanism of Magneto-Rotational Instability (MRI) is examined through analytical quasilinear theory and through nonlinear computation of a single mode in a rotating disk. We find that large-scale magnetic field is generated…

High Energy Astrophysical Phenomena · Physics 2011-02-11 F. Ebrahimi , S. C. Prager , D. D. Schnack

Magnetohydrodynamic instabilities can be responsible for the formation of structures with various scales in astrophysical jets. We consider the stability properties of jets containing both the azimuthal and axial field of subthermal…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Alfio Bonanno , Vadim Urpin

Star formation is enhanced in spiral arms because of a combination of orbit crowding, cloud collisions, and gravitational instabilities. The characteristic mass for the instability is 10^7 Msun in gas and 10^5 Msun in stars, and the…

Astrophysics · Physics 2015-05-13 Bruce G. Elmegreen

A weak fluctuating magnetic field embedded into a turbulent conducting medium grows exponentially while its characteristic scale decays. In the ISM and protogalactic plasmas, the magnetic Pr is very large, so a broad spectrum of growing…

Astrophysics · Physics 2008-11-26 Alexander Schekochihin , Steven Cowley , Jason Maron , Leonid Malyshkin

We report the first successful simulation of spontaneous formation of surface magnetic structures from a large-scale dynamo by strongly-stratified thermal convection in Cartesian geometry. The large-scale dynamo observed in our…

Solar and Stellar Astrophysics · Physics 2016-05-25 Youhei Masada , Takayoshi Sano

Considering two-dimensional potential ideal flow with free surface and finite depth, we study the dynamics of small-amplitude and short-wavelength wavetrains propagating on the background of a steepening nonlinear wave. This can be seen as…

Fluid Dynamics · Physics 2018-08-08 Alexei A. Mailybaev , Andre Nachbin

The back-reaction of the perturbed thermal equilibrium in the solar corona on compressive perturbations, also known as the effect of wave-induced thermal misbalance, is known to result in thermal instabilities chiefly responsible for the…

Solar and Stellar Astrophysics · Physics 2023-01-24 Dmitrii Y. Kolotkov , Valery M. Nakariakov , Joseph B. Fihosy

Dynamo action owing to helically forced turbulence and large-scale shear is studied using direct numerical simulations. The resulting magnetic field displays propagating wave-like behavior. This behavior can be modelled in terms of an…

Astrophysics · Physics 2011-02-11 P. J. Käpylä , A. Brandenburg

We investigate numerically magnetic field generation by thermal convection with square periodicity cells in a rotating horizontal layer of electrically-conducting fluid with stress-free electrically perfectly conducting boundaries for…

Chaotic Dynamics · Physics 2010-04-12 V. Zheligovsky

We study the effect of strong magnetic fields, of the order of $10^{15}-10^{17}$ G, on the extension of the crust of magnetized neutron stars. The dynamical instability region of neutron-proton-electron ($npe$) matter at subsaturation…

Nuclear Theory · Physics 2016-12-14 Jianjun Fang , Sidney Avancini , Helena Pais , Constança Providência

The maximum magnetic field strength generated by Weibel-type plasma instabilities is estimated for typical conditions in the interstellar medium. The relevant kinetic dispersion relations are evaluated by conducting a parameter study both…

High Energy Astrophysical Phenomena · Physics 2015-06-16 R. C. Tautz , J. Triptow

The magnetic Rayleigh-Taylor instability has been shown to play a key role in many astrophysical systems. The equation for the growth rate of this instability in the incompressible limit, and the most-unstable mode that can be derived from…

Solar and Stellar Astrophysics · Physics 2016-10-27 Andrew Hillier

The tearing mode instability is one important mechanism that may explain the triggering of fast magnetic reconnection in astrophysical plasmas such as the solar corona and the Earth's magnetosphere. In this paper, the linear stability…

Plasma Physics · Physics 2020-11-04 Chen Shi , Marco Velli , Fulvia Pucci , Anna Tenerani , Maria Elena Innocenti

A connection between kinetic processes and intermittent turbulence is observed in the solar wind plasma using measurements from the Wind spacecraft at 1 AU. In particular, kinetic effects such as temperature anisotropy and plasma heating…

Space Physics · Physics 2013-12-04 K. T. Osman , W. H. Matthaeus , B. Hnat , S. C. Chapman

We investigate the possible development of magnetohydrodynamical instabilities in the EULAG-MHD "millenium simulation" of Passos & Charbonneau (2014). This simulation sustains a large-scale magnetic cycle characterized by solar-like…

Solar and Stellar Astrophysics · Physics 2015-11-11 N. Lawson , A. Strugarek , P. Charbonneau

Incompressible Magnetohydrodynamics is often assumed to describe solar wind turbulence. We use extended self similarity to reveal scaling in structure functions of density fluctuations in the solar wind. Obtained scaling is then compared…

Astrophysics · Physics 2009-11-10 Bogdan Hnat , Sandra C. Chapman , George Rowlands
‹ Prev 1 8 9 10 Next ›