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In this paper, we briefly introduce the basic questions in the measurements of solar magnetic fields and the possible error sources due to the approximation of the theory of radiation transfer of spectral lines in the solar atmosphere. We…

Solar and Stellar Astrophysics · Physics 2019-12-16 Hongqi Zhang

The effect of shear on the growth of large scale magnetic fields in helical turbulence is investigated. The resulting large-scale magnetic field is also helical and continues to evolve, after saturation of the small scale field, on a slow…

Astrophysics · Physics 2007-05-23 A. Bigazzi , A. Brandenburg , K. Subramanian

Helicity measures complexity in the field. Magnetic helicity is given by a volume integral over the scalar product of magnetic field {\bf B} and its vector potential {\bf A}. A direct computation of magnetic helicity in the solar atmosphere…

Solar and Stellar Astrophysics · Physics 2015-05-20 Sanjiv Kumar Tiwari

Helioseismology revealed an increase in the rotation rate with depth just beneath the solar surface. The relative magnitude of the radial shear is almost constant with latitude. This rotational state can be interpreted as a consequence of…

Solar and Stellar Astrophysics · Physics 2016-06-01 Leonid Kitchatinov

We investigate the fine structure of magnetic fields in the atmosphere of the quiet Sun. We use photospheric magnetic field measurements from {\sc Sunrise}/IMaX with unprecedented spatial resolution to extrapolate the photospheric magnetic…

Solar active regions and sunspots are believed to be formed by the emergence of strong toroidal magnetic flux from the solar interior. Modeling of such events has focused on the dynamics of compact magnetic entities, colloquially known as…

Solar and Stellar Astrophysics · Physics 2021-03-17 Bhishek Manek , Nicholas Brummell

The structure and dynamics of the outer solar atmosphere are reviewed with emphasis on the role played by the magnetic field. Contemporary observations that focus on high resolution imaging over a range of temperatures, as well as UV, EUV…

Solar and Stellar Astrophysics · Physics 2014-12-24 Lyndsay Fletcher , Peter J. Cargill , Spiro K. Antiochos , Boris V. Gudiksen

There is increasingly strong observational evidence that slow magnetoacoustic modes arise in the solar atmosphere. Solar magneto-seismology is a novel tool to derive otherwise directly un-measurable properties of the solar atmosphere when…

Solar and Stellar Astrophysics · Physics 2015-06-04 M. Luna-Cardozo , G. Verth , R. Erdélyi

The relationship between observed structures in the solar atmosphere and the magnetic fields threading them is known only for the solar photosphere, even then imprecisely. We suggest that some of the fine structure in the more tenuous…

Solar and Stellar Astrophysics · Physics 2015-05-27 Philip G. Judge , Alexandra Tritschler , Boon Chye Low

The observations of magnetic field variations as a signature of flaring activity is one of the main goal in solar physics. Some efforts in the past give apparently no unambiguous observations of changes. We observed that the scaling laws of…

The X-ray emission from the Sun reveals a very dynamic hot atmosphere, the corona, which is characterized by a complex morphology and broad range of timescales of variability and spatial structuring. The solar magnetic fields play a…

Solar and Stellar Astrophysics · Physics 2022-06-09 Paola Testa , Fabio Reale

We present evidence of hitherto undiscovered global-scale oscillations in the near-surface shear layer of the Sun. These oscillations are seen as large scale variations of radial shear in both the zonal and meridional flows relative to…

Solar and Stellar Astrophysics · Physics 2023-07-05 Richard S. Bogart , Charles S. Baldner , Sarbani Basu , Rachel Howe , Maria Cristina Rabello Soares

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…

Solar and Stellar Astrophysics · Physics 2023-11-01 Adam J. Finley , Allan Sacha Brun

The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional…

The work is devoted to the study of periodic structures in the magnetic field of the photosphere. The polarity of the Sun's magnetic fields shows cyclicity with periods of 1-3 years, which is possibly due to quasi-biennial variations that…

Solar and Stellar Astrophysics · Physics 2025-07-08 Elena Vernova , Marta Tyasto , Dmitrii Baranov

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

Recently, we have developed a method useful for mapping large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned and calibrated using the synthetic data. Now, we applied the method to the series of…

Astrophysics · Physics 2009-11-13 Michal Svanda , Mirek Klvana , Michal Sobotka , Vaclav Bumba

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

How and where are coronal loops rooted in the solar lower atmosphere? The details of the magnetic environment and its evolution at the footpoints of coronal loops are crucial to understanding the processes of mass and energy supply to the…

The solar wind magnetic field contains rotations at a broad range of scales, which have been extensively studied in the MHD range. Here we present an extension of this analysis to the range between ion and electron kinetic scales. The…

Space Physics · Physics 2015-09-16 C. H. K. Chen , L. Matteini , D. Burgess , T. S. Horbury