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Related papers: Solar dynamo cycle variations with a rotational pe…

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We use the ASH code to model the convective dynamo of solar-type stars. Based on a series of 15 3-D MHD simulations spanning 4 bins in rotation and mass, we show what mechanisms are at work in these stellar dynamos with and without magnetic…

Solar and Stellar Astrophysics · Physics 2022-02-16 Allan Sacha Brun , Antoine Strugarek , Quentin Noraz , Barbara Perri , Jacobo Varela , Kyle Augsutson , Paul Charbonneau , Juri Toomre

The calling card of solar magnetism is the sunspot cycle, during which sunspots regularly reverse their polarity sense every 11 years. However, a number of more complicated time-dependent behaviors have also been identified. In particular,…

Solar and Stellar Astrophysics · Physics 2020-04-06 Loren Matilsky , Juri Toomre

A combination of diamagnetic pumping and a nonlocal alpha-effect of the Babcock-Leighton type in a solar dynamo model helps to reproduce observations of solar magnetic activity. The period of the solar cycle can be reproduced without…

Solar and Stellar Astrophysics · Physics 2015-05-30 L. L. Kitchatinov , S. V. Olemskoy

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…

Astrophysics · Physics 2007-05-23 L. H. Li , S. Sofia

Global and semi-global convective dynamo simulations of solar-like stars are known to show a transition from an anti-solar (fast poles, slow equator) to solar-like (fast equator, slow poles) differential rotation (DR) for increasing…

Solar and Stellar Astrophysics · Physics 2019-11-25 M. Viviani , M. J. Käpylä , J. Warnecke , P. J. Käpylä , M. Rheinhardt

The correlation between geomagnetic activity and the sunspot number in the 11-year solar cycle exhibits long-term variations due to the varying time lag between the sunspot-related and non-sunspot related geomagnetic activity, and the…

Solar and Stellar Astrophysics · Physics 2015-05-18 Katya Georgieva , Boian Kirov

The dynamo process is believed to drive the magnetic activity of stars like the Sun that have an outer convection zone. Large spectroscopic surveys showed that there is a relation between the rotation periods and the cycle periods: the…

Solar and Stellar Astrophysics · Physics 2015-06-17 S. Mathur , R. A. Garcia , J. Ballot , T. Ceillier , D. Salabert , T. S. Metcalfe , C. Regulo , A. Jimenez , S. Bloemen

It is well accepted that the solar cycle originates from a magnetohydrodynamics dynamo deep inside the Sun. Many dynamo models have long been proposed based on a lot of observational constraints. In this paper, using 342 NSO/Kitt Peak solar…

Astrophysics · Physics 2009-06-23 W. B. Song

In this paper we first discuss observational evidence of longitudinal concentrations of magnetic activity in the Sun and rapidly rotating late-type stars with outer convective envelopes. Scenarios arising from the idea of rotationally…

Solar and Stellar Astrophysics · Physics 2015-06-12 M. J. Mantere , Petri J. Käpylä , Jaan Pelt

The Sun, aside from its eleven year sunspot cycle is additionally subject to long term variation in its activity. In this work we analyse a solar-like convective dynamo simulation, containing approximately 60 magnetic cycles, exhibiting…

Solar and Stellar Astrophysics · Physics 2017-10-11 Frederick A. Gent , Maarit J. Käpylä , Jörn Warnecke

The magnetic activity of the Sun, as manifested in the sunspot cycle, originates deep within its convection zone through a dynamo mechanism which involves non-trivial interactions between the plasma and magnetic field in the solar interior.…

Solar and Stellar Astrophysics · Physics 2015-05-13 Dibyendu Nandy

This paper proposes the idea that the observed dependence of stellar activity cycles on rotation rate can be a manifestation of a stronger dependence on the effective temperature. Observational evidence is recalled and theoretical arguments…

Solar and Stellar Astrophysics · Physics 2023-06-26 Leonid Kitchatinov

We have carried out numerical simulations of the convection zone in a K dwarf of 0.7 solar masses rotating at the solar rotation period. We study the convection pattern, the differential rotation and meridional flows, and the…

Solar and Stellar Astrophysics · Physics 2023-01-25 Manfred Küker

The duration of activity growths in solar cycles is on average shorter than the duration of its declines. This asymmetry can result from fluctuations in dynamo parameters. A solar dynamo model with fluctuations in the $\alpha$-effect shows…

Solar and Stellar Astrophysics · Physics 2018-11-07 Leonid Kitchatinov , Alexander Nepomnyashchikh

We attempt to provide a quantitative theoretical explanation for the observations that Ca II H/K emission and X-ray emission from solar-like stars increase with decreasing Rossby number (i.e., with faster rotation). Assuming that these…

Solar and Stellar Astrophysics · Physics 2014-07-30 Bidya Binay Karak , Leonid L. Kitchatinov , Arnab Rai Choudhuri

Our theoretical and numerical analysis have suggested that for low-mass main sequences stars (of the spectral classes from M5 to G0) rotating much faster than the Sun, the generated large-scale magnetic field is caused by the mean-field…

Solar and Stellar Astrophysics · Physics 2024-04-19 N. Kleeorin , I. Rogachevskii , N. Safiullin , R. Gershberg , S. Porshnev

The Sun has a steady 11-year cycle in magnetic activity most well-known by the rising and falling in the occurrence of dark sunspots on the solar disk in visible bandpasses. The 11-year cycle is also manifest in the variations of emission…

Solar and Stellar Astrophysics · Physics 2016-09-19 Ricky Egeland , Willie Soon , Sallie Baliunas , Jeffrey C. Hall , Alexei A. Pevtsov , Gregory W. Henry

We present results from a model for magnetic flux generation and transport in cool stars and a qualitative comparison of models with observations. The method combines an alpha-omega dynamo at the base of the convection zone, buoyant rise of…

Solar and Stellar Astrophysics · Physics 2015-06-03 Emre Işık

Observations of various solar-type stars along decades revealed that they can have magnetic cycles, just like our Sun. An investigation of the relation between their cycle length and rotation period can shed light on the dynamo mechanisms…

Solar and Stellar Astrophysics · Physics 2017-09-20 Raissa Estrela , Adriana Valio

In this work, we have studied the variability and frequency of occurrence of the grand minima using kinematic dynamo models of one solar mass star with different rotation rates and depths of convection zones. We specify the large-scale…

Solar and Stellar Astrophysics · Physics 2022-12-06 Vindya Vashishth