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Polarization data from high mass star formation regions (W51 e2/e8, Orion BN/KL) are used to derive statistical properties of the plane of sky projected magnetic field. Structure function and auto-correlation function are calculated for…

Solar and Stellar Astrophysics · Physics 2015-05-19 Patrick M. Koch , Ya-Wen Tang , Paul T. P. Ho

Scale invariance is a hallmark of many natural systems, including solar flares, where energy release spans a vast range of scales. Recent computational advances, at the level of both algorithmics and hardware, have enabled high-resolution…

Context. The role of magnetic fields during the formation of high-mass stars is not yet fully understood, and the processes related to the early fragmentation and collapse are largely unexplored today. The high-mass star forming region…

Magnetic field extrapolation is a fundamental tool to reconstruct the three-dimensional magnetic field above the solar photosphere. However, the prevalently used force-free field model might not be applicable in the lower atmosphere with…

Solar and Stellar Astrophysics · Physics 2023-07-12 Fu Yu , Jie Zhao , Yang Su , Xiaoshuai Zhu , Yang Guo , Jinhua Shen , Hui Li

Using a recently suggested magneto-morphological classification (MMC, Abramenko, 2021, MNRAS Vol 507) of solar active regions (ARs), we explored 3048 ARs, observed from12 May 1996 to 27 December 2021. Magnetograms were acquired with the…

Solar and Stellar Astrophysics · Physics 2026-01-21 Anastasiya Zhukova , Valentina Abramenko

In this work, we have studied the temporal evolution of some properties of a sample of superactive regions with the aim to single out the most significant for flare activity forecasting. We have investigated properties of 14 superactive…

Solar and Stellar Astrophysics · Physics 2015-05-14 S. Criscuoli , P. Romano , F. Zuccarello , F. Giorgi

Four different methods are applied here to study the precursors of flare activity in the Active Region NOAA 10486. Two approaches track the temporal behaviour of suitably chosen features (one, the weighted horizontal gradient WGM, is…

Solar and Stellar Astrophysics · Physics 2016-10-24 M. B. Korsos , N. Gyenge , T. Baranyi , A. Ludmany

Plasma turbulence is thought to be associated with various physical processes involved in solar flares, including magnetic reconnection, particle acceleration and transport. Using Ramaty High Energy Solar Spectroscopic Imager ({\it RHESSI})…

Solar and Stellar Astrophysics · Physics 2015-05-27 E. P. Kontar , I. G. Hannah , N. H. Bian

The emergence of magnetic flux, its transition to complex configurations, and the pre-eruptive state of active regions are probed using photospheric magnetograms. We aim to pinpoint different evolutionary stages in active regions, explore…

Solar and Stellar Astrophysics · Physics 2024-11-06 I. Kontogiannis , A. G. M. Pietrow , M. K. Druett , E. Dineva , M. Verma , C. Denker

Solar flares are explosions in the solar atmosphere that release intense bursts of short-wavelength radiation and are capable of producing severe space-weather consequences. Flares release free energy built up in coronal fields, which are…

Solar and Stellar Astrophysics · Physics 2020-08-05 Shamik Bhattacharjee , Rasha Alshehhi , Dattaraj B. Dhuri , Shravan M. Hanasoge

A statistical study of 77 solar active regions (ARs) is conducted to investigate the existence of identifiable correlations between the subsurface structural disturbances and the activity level of the active regions. The disturbances…

Solar and Stellar Astrophysics · Physics 2015-12-23 Chia-Hsien Lin

Unstable states of the solar coronal magnetic field structure result in various flare behaviors. In this study, we compared the confined and eruptive flares that occurred under similar magnetic circumstances in the active region 12673, on…

Solar and Stellar Astrophysics · Physics 2025-03-24 Kouhei Teraoka , Daiki Yamasaki , Yusuke Kawabata , Shinsuke Imada , Toshifumi Shimizu

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

It is well known that photospheric flux emergence is an important process for stressing coronal fields and storing magnetic free energy, which may then be released during a flare. The \emph{Helioseismic and Magnetic Imager} (HMI) onboard…

Solar and Stellar Astrophysics · Physics 2015-06-15 Lucas A. Tarr , Dana W. Longcope , Margaret Millhouse

The emergence and magnetic evolution of solar active regions (ARs) of beta-gamma-delta type, which are known to be highly flare-productive, were studied with the SOHO/MDI data in Cycle 23. We selected 31 ARs that can be observed from their…

Solar and Stellar Astrophysics · Physics 2015-08-19 Kan Takizawa , Reizaburo Kitai

Polarisation measurements by the Event Horizon Telescope from M87$^{\ast}$ and Sgr A$^\ast$ suggest that there is a dynamically strong, ordered magnetic field, typical of what is expected of a magnetically arrested accretion disk (MAD). In…

High Energy Astrophysical Phenomena · Physics 2024-07-29 León Salas , Gibwa Musoke , Koushik Chatterjee , Sera Markoff , Oliver Porth , Matthew Liska , Bart Ripperda

Earlier observational studies have used the time evolution of emerging magnetic flux regions at the photosphere to infer their subsurface structures, assuming that the flux structure does not change significantly over the near-surface…

Solar and Stellar Astrophysics · Physics 2016-06-14 Chia-Hsien Lin , Yu-Chen Chen

We present results of a study of intermittency and multifractality of magnetic structures in solar active regions (ARs). Line-of-sight magnetograms for 214 ARs of different flare productivity observed at the center of the solar disk from…

Solar and Stellar Astrophysics · Physics 2010-12-08 Valentyna Abramenko , Vasyl Yurchyshyn

We have experimentally investigated field induced aggregation of nonmagnetic particles confined in a magnetic fluid layer when rotating magnetic fields were applied. After application of a magnetic field rotating in the plane of the fluid…

Soft Condensed Matter · Physics 2009-11-13 Jozef Černák , Geir Helgesen

We analyze the relationship between the flare X-ray peak flux, and characteristics of the Polarity Inversion Line (PIL) and Active Regions (AR), derived from line-of-sight (LOS) magnetograms. The PIL detection algorithm based on a…

Solar and Stellar Astrophysics · Physics 2018-05-29 Viacheslav M Sadykov , Alexander G Kosovichev