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Related papers: Generating buoyant magnetic flux ropes in solar-li…

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Stellar dynamos are driven by complex couplings between rotation and turbulent convection, which drive global-scale flows and build and rebuild stellar magnetic fields. When stars like our sun are young, they rotate much more rapidly than…

Magnetic fields are usually observed in the quiet Sun as small-scale elements that cover the entire solar surface (the `salt and pepper' patterns in line-of-sight magnetograms). By using 3D radiative MHD numerical simulations we find that…

Solar and Stellar Astrophysics · Physics 2015-08-19 I. N. Kitiashvili , A. G. Kosovichev , N. N. Mansour , A. A. Wray

Strong solar flares occur in $\delta $-spots characterized by the opposite-polarity magnetic fluxes in a single penumbra. Sunspot formation via flux emergence from the convection zone to the photosphere can be strongly affected by…

Solar and Stellar Astrophysics · Physics 2022-09-28 Takafumi Kaneko , Hideyuki Hotta , Shin Toriumi , Kanya Kusano

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

We present three-dimensional numerical simulations of a magnetic loop evolving in either a convectively stable or unstable rotating shell. The magnetic loop is introduced in the shell in such a way that it is buoyant only in a certain…

Solar and Stellar Astrophysics · Physics 2015-06-12 L. Jouve , A. S. Brun , G. Aulanier

Many fully convective stars exhibit a wide variety of surface magnetism, including starspots and chromospheric activity. The manner by which bundles of magnetic field traverse portions of the convection zone to emerge at the stellar surface…

Solar and Stellar Astrophysics · Physics 2016-08-17 Maria A. Weber , Matthew K. Browning

Observations reveal that strong solar flares and coronal mass ejections tend to occur in complex active regions characterized by delta-sunspots, spot rotation, sheared polarity inversion lines (PILs), and magnetic flux ropes. Here we report…

Solar and Stellar Astrophysics · Physics 2019-12-11 Shin Toriumi , Hideyuki Hotta

Natural dynamos such as planets and stars generate global scale magnetic field despite the inferred presence of small scale turbulence. Such systems are known as large scale dynamos and are typically driven by convection and influenced by…

Fluid Dynamics · Physics 2022-02-24 Ming Yan , Michael A. Calkins

When stars like our Sun are young they rotate rapidly and are very magnetically active. We explore dynamo action in rapidly rotating suns with the 3-D MHD anelastic spherical harmonic (ASH) code. The magnetic fields built in these dynamos…

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

We have performed a three-dimensional magnetohydrodynamic simulation to study the emergence of a twisted magnetic flux tube from -20,000 km of the solar convection zone to the corona through the photosphere and the chromosphere. The middle…

Solar and Stellar Astrophysics · Physics 2015-06-03 S. Toriumi , T. Yokoyama

We study the influence of a dynamo magnetic field on the buoyant rise and emergence of twisted magnetic flux-ropes, and their influence on the global external magnetic field. We ran 3D MHD numerical simulations using the ASH code and…

Solar and Stellar Astrophysics · Physics 2015-06-15 R. F. Pinto , A. S. Brun

In the quiet Sun, magnetic fields are usually observed as small-scale magnetic elements, `salt and pepper', covering the entire solar surface. By using 3D radiative MHD numerical simulations we demonstrate that these fields are a result of…

Solar and Stellar Astrophysics · Physics 2013-12-05 I. N. Kitiashvili , A. G. Kosovichev , N. N. Mansour , A. A. Wray

We discuss recent advances made in modelling the complex magnetohydrodynamics of the Sun using our anelastic spherical harmonics (ASH) code. We have conducted extensive 3--D simulations of compressible convection in rotating spherical…

Astrophysics · Physics 2007-05-23 Allan Sacha Brun , Juri Toomre

Magnetic field emerges at the surface of the Sun as sunspots and active regions. This process generates a poloidal magnetic field from a rising toroidal flux tube, it is a crucial but poorly understood aspect of the solar dynamo. The…

Solar and Stellar Astrophysics · Physics 2016-07-19 Aaron C. Birch , Hannah Schunker , Douglas C. Braun , Robert Cameron , Laurent Gizon , Björn Löptien , Matthias Rempel

The emergence of magnetic flux from the deep convection zone plays an important role in the solar magnetism, such as the generation of active regions and triggering of various eruptive phenomena, including jets, flares, and coronal mass…

Solar and Stellar Astrophysics · Physics 2024-09-25 Shin Toriumi , Hideyuki Hotta , Kanya Kusano

The emergence of active regions on the Sun is an integral feature of the solar dynamo mechanism. However, details about the generation of active-region-scale magnetism and the journey of this magnetic flux to the photosphere are still in…

Solar and Stellar Astrophysics · Physics 2023-06-13 Maria A. Weber , Hannah Schunker , Laurène Jouve , Emre Işık

Dynamo action refers to energy exchange processes through which magnetic fields are generated at the expense of kinetic energy of the plasma flows. Dynamos can generate magnetic fields across scales larger or smaller than the flows…

We perform idealised numerical simulations of magnetic buoyancy instabilities in a model of the solar tachocline. We introduce a simplified model of magnetic flux pumping in an upper layer (the convection zone), and study the effects of its…

Solar and Stellar Astrophysics · Physics 2015-06-04 Adrian J. Barker , Lara J. Silvers , Michael R. E. Proctor , Nigel O. Weiss

Sunspots and active regions observed on the solar surface are widely believed to be manifestations of compact predominantly-toroidal magnetic field structures (``flux tubes") that emerge by magnetic buoyancy from the deeper interior of the…

Solar and Stellar Astrophysics · Physics 2024-06-21 Bhishek Manek , Nicholas Brummell

The Sun and other cool stars harbouring outer convection zones manifest magnetic activity in their atmospheres. The connection between this activity and the properties of a deep-seated dynamo generating the magnetic flux is not well…

Solar and Stellar Astrophysics · Physics 2015-05-27 Emre Işık , Dieter Schmitt , Manfred Schüssler