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Related papers: Understanding Grand Minima in Solar Activity: Conf…

200 papers

Geomagnetic activity in each phase of the solar cycle consists of 3 parts: (1) a floor below which the geomagnetic activity cannot fall even in the absence of sunspots, related to moderate graduate commencement storms; (2) sunspot-related…

Earth and Planetary Astrophysics · Physics 2015-06-16 B. Kirov , V. N. Obridko , K. Georgieva , E. V. Nepomnyashtaya , B. D. Shelting

The question of possible small-scale dynamo action in the surface layers of the Sun is revisited with realistic 3D MHD simulations. As in other MHD problems, dynamo action is found to be a sensitive function of the magnetic Prandtl number…

Solar and Stellar Astrophysics · Physics 2015-06-11 I. Thaler , H. C. Spruit

We consider to what extent the long-term dynamics of cyclic solar activity in the form of Grand Minima can be associated with random fluctuations of the parameters governing the solar dynamo. We consider fluctuations of the…

Astrophysics · Physics 2014-11-18 D. Moss , D. Sokoloff , I. Usoskin , V. Tutubalin

An overview is given about recent developments and results of comprehensive simulations of magneto-convective processes in the near-surface layers and photosphere of the Sun. Simulations now cover a wide range of phenomena, from whole…

Solar and Stellar Astrophysics · Physics 2015-06-12 Manfred Schüssler

Using the simple model for the description of the GCR modulation in the heliosphere and the sets of parameters discussed in the accompanying paper we model some features of the time and energy behavior of the GCR intensity near the Earth…

Solar and Stellar Astrophysics · Physics 2014-12-01 M. B. Krainev , G. A. Bazilevskaya , M. S. Kalinin , A. K. Svirzhevskaya , N. S. Svirzhevsky

There is mounting evidence that the ejection of magnetic helicity from the solar surface is important for the solar dynamo. Observations suggest that in the northern hemisphere the magnetic helicity flux is negative. We propose that this…

Astrophysics · Physics 2009-11-07 A. Brandenburg , E. G. Blackman , G. R. Sarson

The diagram of indices of coronal and chromospheric activity allowed us to reveal stars where solar-type activity appears and regular cycles are forming. Using new consideration of a relation between coronal activity and the rotation rate,…

Solar and Stellar Astrophysics · Physics 2015-08-06 M. M. Katsova , N. I. Bondar' , M. A. Livshits

The Sun's axisymmetric large-scale flows, differential rotation and meridional circulation, are thought to be maintained by the influence of rotation on the thermal-convective motions in the solar convection zone. These large-scale flows…

Solar and Stellar Astrophysics · Physics 2023-10-27 Hideyuki Hotta , Yuto Bekki , Laurent Gizon , Quentin Noraz , Mark P. Rast

We assess the global-scale dynamo action achieved in a simulation of a sun-like star rotating at three times the solar rate. The 3-D MHD Anelastic Spherical Harmonic code, using slope-limited diffusion, is employed to capture convection and…

Solar and Stellar Astrophysics · Physics 2013-11-01 Kyle Augustson , Allan Sacha Brun , Mark Steven Miesch , Juri Toomre

Self-organization properties of sustained magnetized plasma are applied to selected solar data to understand solar magnetic fields. Torsional oscillations are speed-up and slow-down bands of the azimuthal flow that correlate with the solar…

Solar and Stellar Astrophysics · Physics 2018-07-26 T. R. Jarboe , T. E. Benedett , C. J. Everson , C. J. Hansen , A. C. Hossack , K. D. Morgan , B. A. Nelson , J. M. Penna , D. A. Sutherland

Turbulent magnetic fields fill most of the volume of the solar atmosphere. However, their spatial and temporal variations are still unknown. Since 2007, during the current solar minimum, we are periodically monitoring several wavelength…

Solar and Stellar Astrophysics · Physics 2010-03-23 L. Kleint , S. V. Berdyugina , A. I. Shapiro , M. Bianda

The activity of the Sun as a result of cyclic changes of the global magnetic field is studied. As a consequence of the analysis of magnetic activity of solar-type stars the following power dependencies were found: the dependence between the…

Solar and Stellar Astrophysics · Physics 2015-10-22 E. A. Bruevich , I. K. Rozgacheva

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

Oscillations detected on the solar surface provide a unique possibility for investigations of the interior properties of a star. Through major observational efforts, including extensive observations from space, as well as development of…

Astrophysics · Physics 2008-11-26 J. Christensen-Dalsgaard

All cool main sequence stars including our Sun are thought to have magnetic fields. Observations of the Sun revealed that even in quiet regions small-scale turbulent magnetic fields are present. Simulations further showed that such magnetic…

Solar and Stellar Astrophysics · Physics 2023-02-01 V. Witzke , H. B. Duehnen , A. I. Shapiro , D. Przybylski , T. S. Bhatia , R. Cameron , S. K. Solanki

The 11-year sunspot cycle has many irregularities, the most promi- nent amongst them being the grand minima when sunspots may not be seen for several cycles. After summarizing the relevant observational data about the irregularities, we…

Solar and Stellar Astrophysics · Physics 2015-06-18 Arnab Rai Choudhuri

Magnetic fields emerging from the Sun's interior carry information about physical processes of magnetic field generation and transport in the convection zone. Soon after appearance on the solar surface the magnetic flux gets concentrated in…

Solar and Stellar Astrophysics · Physics 2009-11-13 A. G. Kosovichev

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…

Solar and Stellar Astrophysics · Physics 2018-08-22 Jörn Warnecke

The long-term solar magnetic activity and its cyclical behaviour, which is maintained by a dynamo mechanism, are both still challenging for the astrophysics. In particular, an atypical event occurred between 1645 and 1715 when the solar…

Global dynamo simulations solving the equations of magnetohydrodynamics (MHD) have been a tool of astrophysicists who try to understand the magnetism of the Sun for several decades now. During recent years many fundamental issues in dynamo…

Solar and Stellar Astrophysics · Physics 2011-07-08 P. J. Käpylä