English
Related papers

Related papers: From convective to stellar dynamos

200 papers

Observations of sun-like stars rotating faster than our current sun tend to exhibit increased magnetic activity as well as magnetic cycles spanning multiple years. Using global simulations in spherical shells to study the coupling of…

Solar and Stellar Astrophysics · Physics 2015-05-20 Nicholas J. Nelson , Benjamin P. Brown , Matthew K. Browning , Allan Sacha Brun , Mark S. Miesch , Juri Toomre

We investigate the influence of magnetic field amplification on the core-collapse supernovae in highly magnetized progenitors through three-dimensional simulations. By considering rotating models, we observe a strong correlation between the…

High Energy Astrophysical Phenomena · Physics 2023-12-22 Jin Matsumoto , Tomoya Takiwaki , Kei Kotake

Magnetic fields are ubiquitous in the Universe. Extragalactic disks, halos and clusters have consistently been shown, via diffuse radio-synchrotron emission and Faraday rotation measurements, to exhibit magnetic field strengths ranging from…

The origin and sustenance of large scale galactic magnetic fields has been a long standing and controversial astrophysical problem. Here an alternative to the ``standard'' $\a-\Omega$ mean field dynamo and primordial theories is pursued.…

Astrophysics · Physics 2009-10-30 Eric G. Blackman

Using a rotating flat layer heated from below as an example, we consider effects which lead to stabilizing an exponentially growing magnetic field in magnetostrophic convection in transition from the kinematic dynamo to the full non-linear…

Fluid Dynamics · Physics 2015-05-18 P. Hejda , M. Reshetnyak

We use three-dimensional direct numerical simulations of the helically forced magnetohydrodynamic equations in spherical shell segments in order to study the effects of changes in the geometrical shape and size of the domain on the growth…

Astrophysics · Physics 2010-01-15 Dhrubaditya Mitra , Reza Tavakol , Axel Brandenburg , David Moss

The recent observational, theoretical, and numerical progress made in understanding stellar magnetism is discussed. Particularly, this review will cover the physical processes thought to be at the origin of these magnetic fields and their…

Solar and Stellar Astrophysics · Physics 2017-11-08 Kyle Augustson

M-dwarf stars are well known for the intense magnetic activity that many of them exhibit. In cool stars with near-surface convection zones, this magnetic activity is thought to be driven largely by the interplay of convection and the large…

Solar and Stellar Astrophysics · Physics 2022-03-30 Connor P. Bice , Juri Toomre

We consider dynamo action driven by three-dimensional rotating anelastic convection in a spherical shell. Motivated by the behaviour of the solar dynamo, we examine the interaction of hydromagnetic modes with different symmetries and…

Solar and Stellar Astrophysics · Physics 2016-07-06 Raphaël Raynaud , Steven M. Tobias

Using numerical simulations at moderate magnetic Reynolds numbers up to 220 it is shown that in the kinematic regime, isotropic helical turbulence leads to an alpha effect and a turbulent diffusivity whose values are independent of the…

Astrophysics · Physics 2008-03-10 Sharanya Sur , Axel Brandenburg , Kandaswamy Subramanian

We present a new mechanism for generation of large-scale magnetic field by thermal convection which does not involve the alpha-effect. We consider weakly nonlinear perturbations of space-periodic steady convective magnetic dynamos in a…

Fluid Dynamics · Physics 2015-12-01 Roman Chertovskih , Vladislav Zheligovsky

Spherical solar dynamo simulations are performed. Self-consistent, fully compressible magnetohydrodynamic system with a stably stratified layer below the convective envelope is numerically solved with a newly developed simulation code based…

Solar and Stellar Astrophysics · Physics 2015-06-15 Youhei Masada , Kohei Yamada , Akira Kageyama

Magnetohydrodynamic simulations of fully convective, rotating spheres with volume heating near the center and cooling at the surface are presented. The dynamo-generated magnetic field saturates at equipartition field strength near the…

Astrophysics · Physics 2007-05-23 W. Dobler , M. Stix , A. Brandenburg

Models of rapidly rotating massive stars at low metallicities show significantly different evolution and higher metal yields compared to non-rotating stars. We estimate the spin-down time-scale of rapid rotating non-convective stars…

Solar and Stellar Astrophysics · Physics 2015-05-27 Herbert Ho Bun Lau , Adrian T. Potter , Christopher A. Tout

Models of rotationally-driven dynamos in stellar radiative zones have suggested that magnetohydrodynamic transport of angular momentum and chemical composition can dominate over the otherwise purely hydrodynamic processes. A proper…

Solar and Stellar Astrophysics · Physics 2015-06-05 Adrian T. Potter , Shashikumar M. Chitre , Christopher A. Tout

The role of turbulent effects for dynamos in the Sun and stars continues to be debated. Mean-field (MF) theory provides a broadly used framework to connect these effects to fundamental magnetohydrodynamics. While inaccessible…

Solar and Stellar Astrophysics · Physics 2021-10-06 Jörn Warnecke , Matthias Rheinhardt , Mariangela Viviani , Frederick Gent , Simo Tuomisto , Maarit J. Käpylä

The study of dynamo action in astrophysical objects classically involves two timescales: the slow diffusive one and the fast advective one. We investigate the possibility of field amplification on an intermediate timescale associated with…

Classical Physics · Physics 2009-11-13 Emmanuel Dormy , David Gerard-Varet

Spiral galaxies, including the Milky Way, have large-scale magnetic fields with significant energy densities. The dominant theory attributes these magnetic fields to a large-scale dynamo. We review the current status of dynamo theory and…

Astrophysics of Galaxies · Physics 2023-08-31 Axel Brandenburg , Evangelia Ntormousi

When our Sun was young it rotated much more rapidly than now. Observations of young, rapidly rotating stars indicate that many possess substantial magnetic activity and strong axisymmetric magnetic fields. We conduct simulations of dynamo…

Solar and Stellar Astrophysics · Physics 2009-06-15 Benjamin P. Brown , Matthew K. Browning , Mark S. Miesch , Allan Sacha Brun , Juri Toomre

Much work on turbulent three-dimensional dynamos has been done using triply periodic domains, in which there are no magnetic helicity fluxes. Here we present simulations where the turbulent intensity is still nearly homogeneous, but now…

Solar and Stellar Astrophysics · Physics 2019-02-20 A. Brandenburg