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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

Previously unobservable mirror asymmetry of the solar magnetic field -- a key ingredient of the dynamo mechanism which is believed to drive the 11-year activity cycle -- has now been measured. This was achieved through systematic monitoring…

Solar and Stellar Astrophysics · Physics 2015-05-14 Hongqi Zhang , T. Sakurai , A. Pevtsov , Yu Gao , Haiqing Xu , D. D. Sokoloff , K. Kuzanyan

Employing the standard solar interior model as input we construct a dynamically-consistent nonlinear dynamo model that takes into account the detailed description of the \Lambda- effect, turbulent pumping, magnetic helicity balance, and…

Solar and Stellar Astrophysics · Physics 2018-07-31 V. V. Pipin

The quasilinear mean-field theory for driven MHD turbulence leads to the result that the observed cross helicity <u \cdot b> may directly yield the magnetic eddy diffusivity \eta_{T} of the quiet Sun. In order to model the cross helicity at…

Solar and Stellar Astrophysics · Physics 2015-06-04 G. Ruediger , M. Kueker , R. S. Schnerr

We continue our attempt to connect observational data on current helicity in solar active regions with solar dynamo models. In addition to our previous results about temporal and latitudinal distributions of current helicity (Kleeorin et…

Astrophysics · Physics 2009-11-10 H. Zhang , D. Sokoloff , I. Rogachevskii , D. Moss , V. Lamburt , K. Kuzanyan , N. Kleeorin

Using a 3D non-linear mean-field solar dynamo model, we investigate the magnetic helicity flux and magnetic twist, and tilt parameters of bipolar magnetic regions (BMRs) emerging from the solar convection zone due to the magnetic buoyancy…

Solar and Stellar Astrophysics · Physics 2025-08-04 V. V. Pipin , Shangbin Yang , A. G. Kosovichev

Magnetic helicity is robustly conserved in systems with very large magnetic Reynolds numbers, including most systems of astrophysical interest, and unlike kinetic and magnetic energy is not dissipated at small scales. This plays a major…

Plasma Physics · Physics 2023-04-11 Yossef Zenati , Ethan T. Vishniac

A generalized mean magnetic field induction equation for differential rotators is derived, including a compressibility, and the anisotropy induced on the turbulent quantities from the mean magnetic field itself and a mean velocity shear.…

Astrophysics · Physics 2009-10-31 Eric G. Blackman

A three-dimensional numerical computation of magnetohydrodynamic dynamo behavior is described. The dynamo is mechanically forced with a driving term of the Taylor-Green type. The magnetic field development is followed from negligibly small…

Astrophysics · Physics 2007-05-23 P. D. Mininni , Y. Ponty , D. C. Montgomery , J. -F. Pinton , H. Politano , A. Pouquet

We study the effect of turbulent drift of a large-scale magnetic field that results from the interaction of helical convective motions and differential rotation in the solar convection zone. The principal direction of the drift corresponds…

Solar and Stellar Astrophysics · Physics 2015-06-05 V. V. Pipin

A two-dimensional mean field dynamo model is solved where magnetic helicity conservation is fully included. The model has a negative radial velocity gradient giving rise to equatorward migration of magnetic activity patterns. In addition…

Astrophysics · Physics 2007-05-23 A. Brandenburg , P. J. Käpylä

We consider effects of the harmonic magnetic field boundary conditions at the top of the dynamo domain on the dynamo stability inside the solar convection zone. These boundary conditions allow us to quantify the helical properties of the…

Solar and Stellar Astrophysics · Physics 2025-09-15 V. V. Pipin

Current helicity and twist of solar magnetic fields are important quantities to characterize the dynamo mechanism working in the convection zone of the Sun. We have carried out a statistical study on the current helicity of solar active…

Solar and Stellar Astrophysics · Physics 2015-06-23 Kenichi Otsuji , Takashi Sakurai , Kirill Kuzanyan

We show that the presence of a steady $\ao$ dynamo in astrophysical rotators likely leads to an outflow of relative magnetic helicity and thus magnetic energy available for particle acceleration in a corona. The connection between energy…

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

The generation of solar non-axisymmetric magnetic fields is studied based on a linear alpha2-Omega dynamo model in a rotating spherical frame. The model consists of a solar-like differential rotation, a magnetic diffusivity varied with…

Astrophysics · Physics 2008-11-26 Jie Jiang , Jingxiu Wang

Recent analysis of the helioseismic observations indicate that the previously observed surface torsional oscillations extend significantly downwards into the solar convection zone. In an attempt to understand these oscillations, we study…

Astrophysics · Physics 2007-05-23 Eurico Covas , Reza Tavakol , David Moss , Andrew Tworkowski

In light of new results, the one-dimensional mean-field dynamo model of Brandenburg & Kapyla (2007) with dynamical quenching and a nonlocal Babcock-Leighton alpha effect is re-examined for the solar dynamo. We extend the one-dimensional…

Solar and Stellar Astrophysics · Physics 2015-01-27 A. Brandenburg , A. Hubbard , P. J. Käpylä

Relative magnetic helicity is commonly used in solar physics to avoid the well known gauge ambiguity of standard magnetic helicity in magnetically open domains. But its physical interpretation is difficult owing to the invocation of a…

Solar and Stellar Astrophysics · Physics 2026-01-12 Anthony R. Yeates , Gunnar Hornig

At large magnetic Reynolds numbers, magnetic helicity evolution plays an important role in astrophysical large-scale dynamos. The recognition of this fact led to the development of the dynamical alpha quenching formalism, which predicts…

Solar and Stellar Astrophysics · Physics 2012-03-08 Alexander Hubbard , Axel Brandenburg

Obtaining observational constraints on the role of turbulent effects for the solar dynamo is a difficult, yet crucial, task. Without such knowledge, the full picture of the operation mechanism of the solar dynamo cannot be formed. The…

Solar and Stellar Astrophysics · Physics 2021-10-04 A. P. Prabhu , N. K. Singh , M. J. Käpylä , A. Lagg
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