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We calculate accurate solar models and report the detailed time dependences of important solar quantities. We use helioseismology to constrain the luminosity evolution of the sun and report the discovery of semi-convection in evolved solar…

天体物理学 · 物理学 2008-11-26 John N. Bahcall , M. H. Pinsonneault , Sarbani Basu

Using the non-linear mean-field dynamo models we calculate the magnetic cycle parameters, like the dynamo cycle period, the amplitude of the total magnetic energy, and the Poynting flux luminosity from the surface for the solar analogs with…

太阳与恒星天体物理 · 物理学 2021-01-27 V. V. Pipin

We report the results of a magneto-hydrodynamic (MHD) simulation of a convective dynamo in a model solar convective envelope driven by the solar radiative diffusive heat flux. The convective dynamo produces a large-scale mean magnetic field…

太阳与恒星天体物理 · 物理学 2014-06-18 Yuhong Fan , Fang Fang

A magnetic flux tube may be considered both as a separate body and as a confined field. As a field, it is affected both by the cyclonic convection ($\alpha$-effect) and differential rotation ($\Omega$-effect). As a body, the tube…

天体物理学 · 物理学 2007-05-23 L. H. Li , S. Sofia

The hemispheric asymmetry of sunspot activity observed possesses a regular component varying on a time scale of several solar cycles whose origin and properties are currently debated. This paper addresses the question of whether the…

太阳与恒星天体物理 · 物理学 2019-05-08 Alexander Nepomnyashchikh , Sudip Mandal , Dipankar Banerjee , Leonid Kitchatinov

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…

太阳与恒星天体物理 · 物理学 2025-08-04 V. V. Pipin , Shangbin Yang , A. G. Kosovichev

We derive formulae connecting the frequency variations in the spectrum of solar oscillations to the dynamical quantities that are expected to change over the solar activity cycle. This is done for both centroids and the asymmetric part of…

天体物理学 · 物理学 2009-11-10 W. A. Dziembowski , P. R. Goode

Helioseismology puts strong constraints on the internal sound speed and on the rotation profile in the radiative zone. Young stars of solar type are more active and faster rotators than the Sun. So we begin to build models which include…

太阳与恒星天体物理 · 物理学 2015-05-20 S Turck-Chieze , S Couvidat , V Duez , S Mathis , J Marques , A Palacios , L Piau

Magnetic fields generated in the Sun's interior by the solar dynamo mechanism drive solar activity over a range of time-scales. While space-based observations of the Sun's corona exist only for few decades, direct sunspot observations exist…

太阳与恒星天体物理 · 物理学 2023-07-03 Soumyaranjan Dash , Dibyendu Nandy , Ilya Usoskin

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…

太阳与恒星天体物理 · 物理学 2015-05-14 Hongqi Zhang , T. Sakurai , A. Pevtsov , Yu Gao , Haiqing Xu , D. D. Sokoloff , K. Kuzanyan

We investigate spatio-temporal evolution of high-degree acoustic mode frequencies of the Sun and the surface magnetic activity, over the course of multiple solar cycles, to improve our understanding of the connection between the solar…

太阳与恒星天体物理 · 物理学 2023-12-20 Mackenzie A. Baird , Sushanta C. Tripathy , Kiran Jain

We present the assessment of a diffusion-dominated mean field axisymmetric dynamo model in reproducing historical solar activity and forecast for solar cycle 25. Previous studies point to the Sun's polar magnetic field as an important proxy…

太阳与恒星天体物理 · 物理学 2018-06-29 Alejandro Macario-Rojas , Katharine L. Smith , Peter C. E. Roberts

After emerging to the solar surface, the Sun's magnetic field displays a complex and intricate evolution. The evolution of the surface field is important for several reasons. One is that the surface field, and its dynamics, sets the…

太阳与恒星天体物理 · 物理学 2015-06-22 J. Jiang , D. H. Hathaway , R. H. Cameron , S. K. Solanki , L. Gizon , L. Upton

We propose a novel approach to reconstruct the surface magnetic helicity density on the Sun or sun-like stars. The magnetic vector potential is determined via decomposition of vector magnetic field measurements into toroidal and poloidal…

太阳与恒星天体物理 · 物理学 2019-06-12 Valery V. Pipin , Alexei A. Pevtsov , Yang Liu , Alexander G. Kosovichev

We performed 3D numerical simulations of the solar surface wave field for the quiet Sun and for three models with different localized sound-speed variations in the interior with: (i) deep, (ii) shallow, and (iii) two-layer structures. We…

太阳与恒星天体物理 · 物理学 2012-09-24 Konstantin V. Parchevsky , Junwei Zhao , Thomas Hartlep , Alexander G. Kosovichev

We study the connections between the sun's convection zone and the evolution of the solar wind and corona. We let the magnetic fields generated by a 2.5D axisymmetric kinematic dynamo code (STELEM) evolve in a 2.5D axisymmetric coronal…

太阳与恒星天体物理 · 物理学 2015-05-28 Rui F. Pinto , Allan Sacha Brun , Laurène Jouve , Roland Grappin

We explore the cause of the solar cycle variabilities using a novel 3D Babcock--Leighton dynamo model. In this model, based on the toroidal flux at the base of the convection zone, bipolar magnetic regions (BMRs) are produced with…

太阳与恒星天体物理 · 物理学 2019-01-30 Bidya Binay Karak , Mark Miesch

The strength and morphology of the Sun's magnetic field evolves significantly during the solar cycle, with the overall polarity of the Sun's magnetic field reversing during the maximum of solar activity. Long-term changes are also observed…

太阳与恒星天体物理 · 物理学 2023-11-01 Adam J. Finley , Allan Sacha Brun

The paper address the effects of magnetic helicity conservation in a non-linear nonaxisymmetric mean-field solar dynamo model. We study the evolution of the shallow non-axisymmetric magnetic field perturbation with the strength about 10G in…

太阳与恒星天体物理 · 物理学 2016-01-21 V. V. Pipin

Several solar-like stars exhibit cyclic magnetic activity similar to the Sun as found in photospheric and chromospheric emission. We want to understand the physical mechanism involved in rotational dependence of these activity cycle…

太阳与恒星天体物理 · 物理学 2018-08-22 Jörn Warnecke