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Possibilities and difficulties of applying the theory of magnetic field generation by convection flows in rotating spherical fluid shells to the Giant Planets are outlined. Recent progress in the understanding of the distribution of…

Earth and Planetary Astrophysics · Physics 2009-06-02 F. H. Busse , R. D. Simitev

We review recent advances in modeling global-scale convection and dynamo processes with the Anelastic Spherical Harmonic (ASH) code. In particular, we have recently achieved the first global-scale solar convection simulations that exhibit…

Astrophysics · Physics 2008-11-20 M. S. Miesch , M. K. Browning , A. S. Brun , J. Toomre , B. P. Brown

We present evidence for finite magnetic helicity density in the heliosphere and numerical models thereof, and relate it to the magnetic field properties of the dynamo in the solar convection zone. We use simulations and solar wind data to…

Solar and Stellar Astrophysics · Physics 2012-08-03 Jörn Warnecke , Axel Brandenburg , Dhrubaditya Mitra

Mean-field dynamo theory has important applications in solar physics and galactic magnetism. We discuss some of the many turbulence effects relevant to the generation of large-scale magnetic fields in the solar convection zone. The…

Solar and Stellar Astrophysics · Physics 2023-11-23 Axel Brandenburg , Detlef Elstner , Youhei Masada , Valery Pipin

The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional…

Using two-dimensional magnetohydrodynamics calculations, we investigate a twist gen- eration mechanism on a magnetic flux tube at the base of the solar convection zone based on the idea of Choudhuri, 2003, Sol. Phys., 215, 31 in which a…

Solar and Stellar Astrophysics · Physics 2015-06-11 H. Hotta , T. Yokoyama

Magnetic flux generated and intensified by the solar dynamo emerges into the solar atmosphere, forming active regions (ARs) including sunspots. Existing theories of flux emergence suggest that the magnetic flux can rise buoyantly through…

Solar and Stellar Astrophysics · Physics 2020-06-17 Aiying Duan , Chaowei Jiang , Shin Toriumi , Petros Syntelis

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

A putative temporally varying circulation-free magnetic-field configuration is inferred in an equatorial segment of the solar convection zone from the helioseismologically inferred angular-velocity variation, assuming that the predominant…

Solar and Stellar Astrophysics · Physics 2015-06-11 H. M. Antia , S. M. Chitre , D. O. Gough

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

This study aims at investigating the ability of strong interactions between magnetic field concentrations during their rise through the convection zone to produce complex active regions at the solar surface. To do so, we perform numerical…

Solar and Stellar Astrophysics · Physics 2018-05-02 L. Jouve , A. S. Brun , G. Aulanier

(1)The previous theoretical studies showed that in the presence of the small-scale dynamo the large-scale vorticity can produce the the divergent-type helicity flux breaking the equatorial reflection symmetry of the magnetic fluctuations in…

Solar and Stellar Astrophysics · Physics 2026-01-13 V. V. Pipin

Despite the lack of a shear-rich tachocline region low-mass fully convective stars are capable of generating strong magnetic fields, indicating that a dynamo mechanism fundamentally different from the solar dynamo is at work in these…

Solar and Stellar Astrophysics · Physics 2015-11-11 Rakesh K. Yadav , Ulrich R. Christensen , Julien Morin , Thomas Gastine , Ansgar Reiners , Katja Poppenhaeger , Scott J. Wolk

We simulate the buoyant rise of a magnetic flux rope from the solar convection zone into the corona to better understand the energetic coupling of the solar interior to the corona. The magnetohydrodynamic model addresses the physics of…

Solar and Stellar Astrophysics · Physics 2015-06-03 Fang Fang , Ward Manchester , William P. Abbett , Bart van der Holst

Dynamos in the Sun and other bodies tend to produce magnetic fields that possess magnetic helicity of opposite sign at large and small scales, respectively. The build-up of magnetic helicity at small scales provides an important saturation…

Solar and Stellar Astrophysics · Physics 2010-11-30 Piyali Chatterjee , Gustavo Guerrero , Axel Brandenburg

The magnetic network extending from the photosphere (solar radius $\simeq R_\odot$) to lower corona ($R_\odot + 10$ Mm) plays an important role in the heating mechanisms of the solar atmosphere. Here we further develop the models with…

Solar and Stellar Astrophysics · Physics 2019-08-02 Frederick A. Gent , Ben Snow , Viktor Fedun , Robertus Erdelyi

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

Solar flares and coronal mass ejections, the primary space weather disturbances affecting the entire heliosphere and near-Earth environment, mainly emanate from sunspot regions harbouring high degrees of magnetic twist. However, it is not…

Solar and Stellar Astrophysics · Physics 2023-06-01 Shin Toriumi , Hideyuki Hotta , Kanya Kusano

The transport dynamo mechanism, which describes the magnetic field generation by diffusion flow is reviewed. In this mechanism, the cross-field transport caused by the random motion of fluid breaks the frozen-flux approximation, and the…

Fluid Dynamics · Physics 2021-10-07 Chang-Mo Ryu

The leading theoretical paradigm for the Sun's magnetic cycle is an $\alpha\omega$-dynamo process, in which a combination of differential rotation and turbulent, helical flows produces a large-scale magnetic field that reverses every 11…

Solar and Stellar Astrophysics · Physics 2023-01-16 Craig D. Duguid , Paul J. Bushby , Toby S. Wood