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Related papers: Intermittency spectra of current helicity in solar…

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$PSP$ and $SolO$ data are utilized to investigate magnetic field intermittency in the solar wind (SW). Small-scale intermittency $(20-100d_{i})$ is observed to radially strengthen when methods relying on higher-order moments are considered…

Statistical properties of the Sun's photospheric turbulent magnetic field, especially those of the Active Regions (ARs), have been studied using the line-of-sight data from magnetograms taken by SOHO and several other instruments (see e.g.…

Solar and Stellar Astrophysics · Physics 2013-07-17 Shiva Kumar. Malapaka , Wolf-Christian Mueller

We present a study of multi-wavelength observations, of a C 2.3 solar flare in Active Region NOAA 12353, observed on 2015 May 23, which reveal new properties of acoustic waves in the flaring region. The space-, and ground-based data…

Solar and Stellar Astrophysics · Physics 2022-03-07 A. Wisniewska , E. Chmielewska , K. Radziszewski , M. Roth , J. Staiger

This first paper in a series describes the design of a study testing whether pre-appearance signatures of solar magnetic active regions were detectable using various tools of local helioseismology. The ultimate goal is to understand…

Solar and Stellar Astrophysics · Physics 2013-03-07 K. D. Leka , G. Barnes , A. C. Birch , I. Gonzalez-Hernandez , T. Dunn , B. Javornik , D. C. Braun

The results of determinations of the azimuthal and meridional velocities by time-distance helioseismology from Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO) from May 2010 to September 2020 at latitudes from…

Solar and Stellar Astrophysics · Physics 2021-02-26 Alexander V. Getling , Alexander G. Kosovichev , Junwei Zhao

To create early warning capabilities for upcoming Space Weather disturbances, we have selected a dataset of 61 emerging active regions, which allows us to identify characteristic features in the evolution of acoustic power density to…

Solar and Stellar Astrophysics · Physics 2024-12-25 Spiridon Kasapis , Irina N. Kitiashvili , Alexander G. Kosovichev , John T. Stefan , Bhairavi Apte

Context. The High Resolution Telescope of the Polarimetric and Helioseismic Imager on Solar Orbiter (SO/PHI-HRT) operates in an extreme observational environment, observing the Sun as close as $0.28$ au. The high thermal load and large…

We study the role of rotating sunspots in relation to the evolution of various physical parameters characterizing the non-potentiality of the active region NOAA 11158 and its eruptive events using the magnetic field data from the…

Solar and Stellar Astrophysics · Physics 2015-06-11 P. Vemareddy , A. Ambastha , R. A. Maurya

Aims. Moreno-Insertis et al. (2018) recently discovered two types of flux emergence in their numerical simulations: magnetic loops and magnetic sheet emergence. Whereas magnetic loop emergence has been documented well in the last years, by…

Solar and Stellar Astrophysics · Physics 2019-02-13 C. E. Fischer , J. M. Borrero , N. Bello González , A. J. Kaithakkal

Using magnetographic data provided by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, we analyzed the structure of magnetic fields and vertical electric currents in six active regions (ARs) with different level…

Solar and Stellar Astrophysics · Physics 2020-02-19 Yuriy A. Fursyak , Alexander S. Kutsenko , Valentina I. Abramenko

An investigation of helicity injection by photospheric shear motions is carried out for two active regions(ARs), NOAA 11158 and 11166, using line-of-sight magnetic field observations obtained from the Helioseismic and Magnetic Imager…

Solar and Stellar Astrophysics · Physics 2015-06-04 P. Vemareddy , A. Ambastha , R. A. Maurya , J. Chae

Aims. To study intensity oscillations in the solar chromosphere/corona above a quiet-Sun magnetic network. Methods. We analyse the time series of He II 256.32, Fe XI 188.23 and Fe XII 195.12 spectral lines observed by EUV Imaging…

Astrophysics · Physics 2009-11-13 A. K. Srivastava , D. Kuridze , T. V. Zaqarashvili , B. N. Dwivedi

We analyze the complete chain of effects caused by a solar eruptive event in order to better understand the dynamic evolution of magnetic-field related quantities in interplanetary space, in particular that of magnetic flux and helicity. We…

Solar and Stellar Astrophysics · Physics 2023-01-11 J. K. Thalmann , M. Dumbovic , K. Dissauer , T. Podladchikova , G. Chikunova , M. Temmer , E. Dickson , A. M. Veronig

The injection of magnetic helicity into the heliosphere during solar cycle 24 and the early phase of cycle 25 has been calculated based on the analysis of a series of synoptic magnetic charts. During the cycle, the injected magnetic…

Solar and Stellar Astrophysics · Physics 2025-07-28 H. Q. Zhang , S. B. Yang , K. M. Kuzanyan , Axel Brandenburg , H. Q. Xu , D. D. Sokoloff

Context. Relative field line helicity (RFLH) is a recently developed quantity which can approximate the density of relative magnetic helicity. Aims. This paper aims to determine whether RFLH can be used as an indicator of solar eruptivity.…

Solar and Stellar Astrophysics · Physics 2023-12-22 K. Moraitis , S. Patsourakos , A. Nindos , J. K. Thalmann , É. Pariat

The Sun is the only star where the superficial turbulent convection can be observed at very high spatial resolution. The Solar Dynamics Observatory (SDO) has continuously observed the full Sun from space with multi-wavelength filters since…

Solar and Stellar Astrophysics · Physics 2021-08-18 J. Ballot , T. Roudier , J. M. Malherbe , Z. Frank

Wave theories of heating the chromosphere, corona, and solar wind due to photospheric fluctuations are strengthened by the existence of observed wave coherency up to the transition region (TR). The coherency of solar spicules' intensity…

Solar and Stellar Astrophysics · Physics 2017-02-08 Alireza Ahangarzadeh Maralani , Ehsan Tavabi , Ali Ajabshirizadeh

Using time-sequence vector magnetic field and coronal observations from \textit{Solar Dynamics Observatory}, we report the observations of the magnetic field evolution and coronal activity in four emerging active regions (ARs). The ARs…

Solar and Stellar Astrophysics · Physics 2022-08-24 P. Vemareddy

This study identifies the solar origins of magnetic clouds that are observed at 1 AU and predicts the helical handedness of these clouds from the solar surface magnetic fields. We started with the magnetic clouds listed by the Magnetic…

Solar and Stellar Astrophysics · Physics 2018-11-09 Roger K. Ulrich , Pete Riley , T. Tran

Understanding and monitoring solar active regions is essential for operational space-weather forecasting and improved solar dynamo modeling. This requires comprehensive 360-degree observations of the Sun. While space-weather forecasting has…

Solar and Stellar Astrophysics · Physics 2026-03-04 Amr Hamada , Kiran Jain , Hanna Strecker , Charles Lindsey , David Orozco Suarez