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The topology and dynamics of the solar chromosphere are greatly affected by the presence of magnetic fields. The magnetic field can be inferred by analyzing polarimetric observations of spectral lines. Polarimetric signals induced by…

Solar and Stellar Astrophysics · Physics 2019-09-11 C. J. Díaz Baso , J. de la Cruz Rodríguez , S. Danilovic

The distribution and evolution of the magnetic field at the solar poles through a solar cycle is an important parameter in understanding the solar dynamo. The accurate observations of the polar magnetic flux is very challenging from the…

Solar and Stellar Astrophysics · Physics 2024-07-26 Sanjay Gosain , Han Uitenbroek

In this dataset we provide a comprehensive collection of magnetograms (images quantifying the strength of the magnetic field) from the National Aeronautics and Space Administration's (NASA's) Solar Dynamics Observatory (SDO). The dataset…

Solar and Stellar Astrophysics · Physics 2024-02-13 Laura E. Boucheron , Ty Vincent , Jeremy A. Grajeda , Ellery Wuest

Reconstructions of past irradiance variations require suitable data on solar activity. The longest direct proxy is the sunspot number, and it has been most widely employed for this purpose. These data, however, only provide information on…

Solar and Stellar Astrophysics · Physics 2019-05-15 Theodosios Chatzistergos , Ilaria Ermolli , Natalie A. Krivova , Sami K. Solanki

We present an in-depth characterization of the polarimetric channel of the Large-Angle Spectrometric COronagraph LASCO-C2 onboard the Solar and Heliospheric Observatory (SoHO). The polarimetric analysis of the white-light images makes use…

Solar and Stellar Astrophysics · Physics 2020-07-21 Philippe Lamy , Antoine Llebaria , Brice Boclet , Hugo Gilardy , Michael Burtin , Olivier Floyd

Direct remote-sensing observations of the solar poles have been hindered by the restricted view obtained from the ecliptic plane. For the first time ever, Solar Orbiter with its remote-sensing instruments observed the poles of the Sun from…

Solar irradiance variations across various timescales, from minutes to centuries, represents a potential natural driver of past regional and global climate cold phases. To accurately assess the Sun's effect on climate, particularly during…

The long-term monitoring of magnetic cycles in cool stars is a key diagnostic in understanding how dynamo generation and amplification of magnetic fields occur in stars similar in structure to the Sun. We investigate the temporal evolution…

Using the reconstruction of power input to the magnetosphere given in Paper 1 (arXiv:1708.04904), we reconstruct annual means of geomagnetic indices over the past 400 years to within a 1-sigma error of +/-20 pc. In addition, we study the…

Earth and Planetary Astrophysics · Physics 2018-01-09 Mike Lockwood , Mathew J. Owens , Luke A. Barnard , Chris J. Scott , Clare E. Watt , Sarah Bentley

Although the magnetic fields in the quiet Sun account for the majority of the magnetic energy in the solar photosphere, inferring their exact spatial distribution, origin, and evolution poses an important challenge because the signals lie…

Solar and Stellar Astrophysics · Physics 2024-10-03 Elias Ebert , Ivan Milic , Juan Manuel Borrero

Various observatories around the globe started regular full-disk imaging of the solar atmosphere in the Ca II K line since the early decades of the 20th century. The archives made by these observations have the potential of providing far…

Astrophysics · Physics 2008-02-27 I. Ermolli , S. K. Solanki , A. G. Tlatov , N. A. Krivova , R. K. Ulrich , J. Singh

Presented here is a review of present knowledge of the long-term behavior of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method. The concept of solar activity is discussed along with an overview…

Astrophysics · Physics 2016-10-19 Ilya G. Usoskin

Distribution of the positive and negative photospheric fields is studied on the base of synoptic maps of the photospheric magnetic field produced by the National Solar Observatory Kitt Peak (NSO Kitt Peak) for 1976-2016. In the analysis…

Solar and Stellar Astrophysics · Physics 2019-02-20 E. S. Vernova , M. I. Tyasto , D. G. Baranov , O. A. Danilova

The polar precursor method is widely considered to be the most robust physically motivated method to predict the amplitude of an upcoming solar cycle.It uses indicators of the magnetic field concentrated near the poles around sunspot…

Solar and Stellar Astrophysics · Physics 2022-02-09 Pawan Kumar , Melinda Nagy , Alexandre Lemerle , Bidya Binay Karak , Kristof Petrovay

The solar magnetic activity cycle is responsible for periodic episodes of severe space weather, which can perturb satellite orbits, interfere with communications systems, and bring down power grids. Much progress has recently been made in…

Astrophysics · Physics 2007-05-23 T. S. Metcalfe , T. J. Henry , M. Knolker , D. R. Soderblom

Variations of the solar UV irradiance are an important driver of chemical and physical processes in the Earth's upper atmosphere and may also influence global climate. Here we reconstruct solar UV irradiance in the range 115-400 nm over the…

Solar and Stellar Astrophysics · Physics 2009-11-23 N. A. Krivova , S. K. Solanki , T. Wenzler , B. Podlipnik

Magnetic fields, which play a major role in a large number of astrophysical processes from galactic to cosmological scales, can be traced via observations of dust polarization as demonstrated by the Planck satellite results. In particular,…

Predicting geomagnetic conditions based on in-situ solar wind observations allows us to evade disasters caused by large electromagnetic disturbances originating from the Sun to save lives and protect economic activity. In this study, we…

Space Physics · Physics 2022-10-12 Ryozo Kitajima , Motoharu Nowada , Ryotaro Kamimura

Geomagnetic activity is often described using summary indices to summarize the likelihood of space weather impacts, as well as when parameterizing space weather models. The geomagnetic index $\text{K}_\text{p}$ in particular, is widely used…

Space Physics · Physics 2020-07-07 S. Chakraborty , S. K. Morley

Total solar irradiance variations, about 0.1% between solar activity maximum and minimum, are available from accurate satellite measurements since 1978 and thus do not provide useful information on longer-term secular trends. Recently,…

Solar and Stellar Astrophysics · Physics 2012-05-23 S. Sello