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One of the main theories for heating of the solar corona is based on the idea that solar convection shuffles and tangles magnetic field lines to make many small-scale current sheets that, via reconnection, heat coronal loops. Tiwari et al…

Solar and Stellar Astrophysics · Physics 2025-05-08 V. Aparna , Sanjiv K. Tiwari , Ronald L. Moore , Navdeep K. Panesar , Brian Welsch , Bart De Pontieu , Aimee Norton

Magnetic reconnection plays an important role in converting energy while modifying field topology. This process takes place in varied plasma environments in which the transport of magnetic flux is intrinsic. Identifying active magnetic…

Space Physics · Physics 2022-03-15 Yi Qi , Tak Chu Li , Christopher T. Russell , Robert E. Ergun , Ying-Dong Jia , Mark Hubbert

Spectropolarimetric observations show that many low-mass stars possess large-scale poloidal magnetic fields with considerable dipole component, which in some cases exhibit temporal dynamics - cycles or reversals. Although it is widely…

Solar and Stellar Astrophysics · Physics 2025-07-02 Anna Guseva , Ludovic Petitdemange , Charly Pinçon

A particle with internal unobserved states diffusing in a force field will generally display effective advection-diffusion. The drift velocity is proportional to the mobility averaged over the internal states, or effective mobility, while…

Statistical Mechanics · Physics 2017-10-13 Erik Aurell , Stefano Bo

We study the relationship between full-disk solar radiative flux at different wavelengths and average solar photospheric magnetic-flux density, using daily measurements from the Kitt Peak magnetograph and other instruments extending over…

Solar and Stellar Astrophysics · Physics 2010-06-23 Dora Preminger , Dibyendu Nandy , Gary Chapman , Petrus C. H. Martens

The Sun is a magnetic star whose magnetism and cyclic activity is linked to the existence of an internal dynamo. We aim to understand the establishment of the solar magnetic 22-yr cycle, its associated butterfly diagram and field parity…

Astrophysics · Physics 2008-11-26 L. Jouve , A. S. Brun

The dynamics of horizontal plasma flows during the first hours of the emergence of active region magnetic flux in the solar photosphere have been analyzed using SOHO/MDI data. Four active regions emerging near the solar limb have been…

Solar and Stellar Astrophysics · Physics 2017-05-01 A. Khlystova

We present a three-dimensional numerical model for the generation and evolution of the magnetic field in the solar convection zone, in which sunspots are produced and contribute to the cyclic reversal of the large-scale magnetic field. We…

Solar and Stellar Astrophysics · Physics 2018-01-30 Rohit Kumar , Laurène Jouve , Rui F. Pinto , Alexis P. Rouillard

The meridional circulation at high latitudes is crucial to the build-up and reversal of the Sun's polar magnetic fields. Here we characterize the axisymmetric flows by applying a magnetic feature cross-correlation procedure to high…

Solar and Stellar Astrophysics · Physics 2013-03-26 Lisa Rightmire-Upton , David H. Hathaway , Katie Kosak

Polar fields in solar cycle 23 were about 50% weaker than those in cycle 22. The only theoretical models which have addressed this puzzle are surface transport models and flux-transport dynamo models. Comparing polar fields obtained from…

Solar and Stellar Astrophysics · Physics 2015-05-27 Mausumi Dikpati

The axisymmetric 3-D MHD outflow of a cold plasma from a magnetized and rotating astrophysical object is numerically simulated with the purpose of investigating the outflow's magnetocentrifugal acceleration and eventual collimation. Gravity…

Astrophysics · Physics 2009-10-31 S. Bogovalov , K. Tsinganos

An explanation is presented for the rather strong total surface differential rotation of the observed very young solar-type stars like AB Dor and PZ Tel. Due to its rapid rotation a nonuniform energy flux leaves the stellar core so that the…

Astrophysics · Physics 2016-08-16 G. Rüdiger , M. Küker

The effect of solar rotation on the proton-alpha differential flow speed, $v_{\alpha p}$, and consequently on the angular momentum transport in the solar wind, is explored. It is found that the force introduced by the azimuthal components…

Astrophysics · Physics 2011-02-11 Bo Li , Shadia Rifai Habbal , Xing Li

Mean-field hydrodynamics advanced to clear explanations for the origin and properties of the global meridional flow in stellar convection zones. Qualitative arguments and analysis of basic equations both show that the meridional circulation…

Solar and Stellar Astrophysics · Physics 2017-03-08 L. L. Kitchatinov

We study the effect of turbulent drift of a large-scale magnetic field that results from the interaction of helical convective motions and differential rotation in the solar convection zone. The principal direction of the drift corresponds…

Solar and Stellar Astrophysics · Physics 2015-06-05 V. V. Pipin

There is evidence for coronal plasma flows to break down into fragments and to be laminar. We investigate this effect by modeling flows confined along magnetic channels. We consider a full MHD model of a solar atmosphere box with a dipole…

Solar and Stellar Astrophysics · Physics 2017-12-27 A. Petralia , F. Reale , P. Testa

We report on new spectro-polarimetric measurements with simultaneous filter imaging observation, revealing the frequent appearance of polarization signals indicating high-speed, probably supersonic, downflows that are associated with at…

As well known, magnetic fields in space are distributed very inhomogeneously. Some-times field distributions have forms of filaments with high magnetic field values. As many ob-servations show, such a filamentation takes place in convective…

Solar and Stellar Astrophysics · Physics 2024-03-03 Evgeny A. Kuznetsov , Evgeny A. Mikhailov

We compare the zonal flow pattern in subsurface layers of the Sun with the distribution of surface magnetic features like sunspots and polar faculae. We demonstrate that in the activity belt, the butterfly pattern of sunspots coincides with…

Astrophysics · Physics 2009-11-13 K. R. Sivaraman , H. M. Antia , S. M. Chitre , V. V. Makarova

We address the problem of calculating the transverse magnetic field in the solar wind outside of the hypothetical sphere called the source surface where the solar wind originates. This calculation must overcome a widely used fundamental…

Solar and Stellar Astrophysics · Physics 2016-04-27 Roger K. Ulrich , Tham Tran