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Related papers: Estimation of Polar Magnetic Fields using Ca II K …

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The emission in the near ultraviolet Ca II H & K lines is modulated by stellar magnetic activity. Although this emission, quantified via the S-index, has been serving as a prime proxy of stellar magnetic activity for several decades, many…

Solar and Stellar Astrophysics · Physics 2021-06-23 K. Sowmya , A. I. Shapiro , V. Witzke , N. -E. Nèmec , T. Chatzistergos , K. L. Yeo , N. A. Krivova , S. K. Solanki

Solar flares, especially C, M, and X class, pose significant risks to satellite operations, communication systems, and power grids. We present a novel approach for predicting extreme solar flares using HMI intensitygrams and magnetograms.…

Solar and Stellar Astrophysics · Physics 2026-01-09 Juyoung Yun , Jungmin Shin

We have used semi-synthetic records of emerging sunspot groups based on sunspot number data as input for a surface flux transport model to reconstruct the evolution of the large-scale solar magnetic field and the open heliospheric flux from…

Solar and Stellar Astrophysics · Physics 2015-05-27 Jie Jiang , Robert H. Cameron , Dieter Schmitt , M. Schuessler

This work combines new observations of NIR starlight linear polarimetry with previously simulated observations in order to constrain dynamo models of the Galactic magnetic field. Polarimetric observations were obtained with the Mimir…

Astrophysics of Galaxies · Physics 2015-06-04 Michael D. Pavel , Dan P. Clemens , April F. Pinnick

The polarization of light is a critically under-utilized, rich source of information in astronomy. For stars in particular, surface magnetism polarization that can be detected and measured with spectro-polarimetry. Many questions about…

Local scaling and singularity properties of solar wind and geomagnetic time series were analysed using H\"{o}lder exponents $\alpha$. It was shown that in analysed cases due to multifractality of fluctuations $\alpha$ changes from point to…

Computational Physics · Physics 2020-01-29 Z. Vörös , D. Jankovičová

Magnetic field couples the solar interior to the solar atmosphere, known as the corona. The coronal magnetic field is one of the crucial parameters which determines the coronal structures and regulates the space weather phenomena like…

Solar and Stellar Astrophysics · Physics 2022-07-26 Devojyoti Kansabanik , Divya Oberoi , Surajit Mondal

This article presents a publicly available, multimodal, tiered magnetic polarity inversion lines (MPILs) dataset extracted from the Solar Dynamics Observatory's (SDO) Helioseismic and Magnetic Imager (HMI) Active Region Patches (SDO/HMI…

Solar and Stellar Astrophysics · Physics 2025-08-26 Ziba Khani , Anli Ji , Manolis K. Georgoulis , Berkay Aydin

Solar irradiance is considered one of the main natural factors affecting terrestrial climate, and its variations are included in most numerical models estimating the effects of natural versus anthropogenic factors for climate change. Solar…

Solar and Stellar Astrophysics · Physics 2014-11-25 Katya Georgieva , Yury Nagovitsyn , Boian Kirov

We study the quiet Sun magnetic fields using spectropolarimetric observations of the infrared and visible Fe I lines at 6301.5, 6302.5, 15648 and 15653 A. Magnetic field strengths and filling factors are inferred by the simultaneous fit of…

Astrophysics · Physics 2008-11-26 Itahiza Dominguez Cerdena , Jorge Sanchez Almeida , Franz Kneer

The Galactic Faraday depth sky is a tracer for both the Galactic magnetic field and the thermal electron distribution. It has been previously reconstructed from polarimetric measurements of extra-galactic point sources. Here, we improve on…

Astrophysics of Galaxies · Physics 2020-01-29 Sebastian Hutschenreuter , Torsten A. Enßlin

Solar plages, which are bright regions on the Sun's surface, are an important indicator of solar activity. In this study, we propose an automated algorithm for identifying solar plages in Ca K wavelength solar data obtained from the…

Solar and Stellar Astrophysics · Physics 2023-07-17 Sarvesh Gharat , Bhaskar Bose , Abhimanyu Borthakur , Rakesh Mazumder

The solar group at the National Astronomical Observatory of Japan is conducting synoptic solar observations with the Solar Flare Telescope. While it is a part of a long-term solar monitoring, contributing to the study of solar dynamo…

Solar and Stellar Astrophysics · Physics 2020-09-29 Yoichiro Hanaoka , Takashi Sakurai , Ken'ichi Otsuji , Isao Suzuki , Satoshi Morita

The presence of the magnetic field is critical to transport energy through the solar atmosphere. The new generation of telescopes will provide new insight into how the magnetic field arrives into the chromosphere and its role in the energy…

Solar and Stellar Astrophysics · Physics 2022-11-17 Juan Martínez-Sykora , Alberto Sainz Dalda , Milan Gošić , Bart De Pontieu

The variability in the magnetic activity of the Sun is the main source of the observed changes in the plasma and electromagnetic environments within the heliosphere. The primary way in which solar activity affects the Earth's environment is…

Solar and Stellar Astrophysics · Physics 2024-05-27 Raffaele Reda , Mirko Stumpo , Luca Giovannelli , Tommaso Alberti , Giuseppe Consolini

We describe here a procedure to combine measurements in the 393.37 nm Ca II K spectral line taken at different observatories. Measurements from the National Solar Observatory (NSO) Integrated Sunlight Spectrometer (ISS) on the Synoptic…

Solar and Stellar Astrophysics · Physics 2017-02-06 Luca Bertello , Andrew R. Marble , Alexei A. Pevtsov

The Helioseismic and Magnetic Imager (HMI) has just started producing data that will help determine what the sources and mechanisms of variability in the Sun's interior are. The instrument measures the Doppler shift and the polarization of…

Solar and Stellar Astrophysics · Physics 2010-12-20 Rebecca Centeno , Steve Tomczyk , Juan Manuel Borrero , Sebastien Couvidat , Keiji Hayashi , Todd Hoeksema , Yang Liu , Jesper Schou

We could infer a secular decreasing trend in the poloidal to toroidal solar magnetic flux amplification factor ( Af) using geomagnetic observations ( classic and IHV corrected aa indices) during the sunspot cycles 9-23. A similar decreasing…

General Physics · Physics 2010-12-23 T. E. Girish , G. Gopkumar

We use the first publically available data from the Daniel K. Inouye Solar Telescope (DKIST) to track magnetic connections from the solar photosphere into the corona. We scrutinize relationships between chromospheric magnetism and bright…

Solar and Stellar Astrophysics · Physics 2023-11-03 Philip Judge , Lucia Kleint , Roberto Casini , Alfred de Wijn , Tom Schad , Alexandra Tritschler

Starlight polarimetry, when combined with accurate distance measurements, allows for exploration of the three-dimensional structure of local magnetic fields in great detail. We present optical polarimetric observations of stars in and close…