Results 1 to 10 of about 33,356 (264)

What Are the Causes of Super Activity of Solar Active Regions? [PDF]

The Astrophysical Journal, 2023
Flare productivity varies among solar active regions (ARs). This study analyzed 20 ARs of contrasting sunspot areas and flare productivities to understand the super flare productivity of certain ARs.
Suman K. Dhakal, Jie Zhang
doaj   +2 more sources

Direct evidence that twisted flux tube emergence creates solar active regions. [PDF]

Nat Commun, 2021
MacTaggart D, Prior C, Raphaldini B, Romano P, Guglielmino SL.   +4 more
europepmc   +2 more sources

Dynamics of Subsurface Flows in Solar Active Regions during the 2024 May Storm

The Astrophysical Journal
In 2024 May, the Sun exhibited intense magnetic activity, marked by numerous high-intensity flares resulting from the interaction and merging of NOAA active regions (ARs) 13664 and 13668 in the southern hemisphere and AR 13663 in the northern hemisphere.
B. Lekshmi, Sushanta Tripathy, Kiran Jain, Alexei Pevtsov   +3 more
doaj   +2 more sources

Intriguing Plasma Composition Pattern in a Solar Active Region: A Result of Nonresonant Alfvén Waves?

The Astrophysical Journal, 2023
The plasma composition of the solar corona is different from that of the solar photosphere. Elements that have a low first ionization potential (FIP) are preferentially transported to the corona and therefore show enhanced abundances in the corona ...
Teodora Mihailescu, David H. Brooks, J. Martin Laming, Deborah Baker, Lucie M. Green, Alexander W. James, David M. Long, Lidia van Driel-Gesztelyi, Marco Stangalini   +8 more
doaj   +1 more source

Deep Learning–based Solar Flare Forecasting Model. III. Extracting Precursors from EUV Images

The Astrophysical Journal Supplement Series, 2023
A solar flare is one of the most intense solar activities, and flare forecasting is necessary to avoid its destructive impact on the near-Earth space environment and technological infrastructure.
Dezhi Sun, Xin Huang, Zhongrui Zhao, Long Xu   +3 more
doaj   +1 more source

Properties of Flare-imminent versus Flare-quiet Active Regions from the Chromosphere through the Corona. I. Introduction of the AIA Active Region Patches (AARPs)

The Astrophysical Journal, 2023
We begin here a series of papers examining the chromospheric and coronal properties of solar active regions. This first paper describes an extensive data set of images from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory curated for ...
Karin Dissauer, K. D. Leka, Eric L. Wagner   +2 more
doaj   +1 more source

Spectro-polarimetric Properties of Sunquake Sources in X1.5 Flare and Evidence for Electron and Proton Beam Impacts

The Astrophysical Journal, 2023
The first significant sunquake event of Solar Cycle 25 was observed during the X1.5 flare of 2022 May 10, by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory.
Alexander G. Kosovichev, Viacheslav M. Sadykov, John T. Stefan   +2 more
doaj   +1 more source

High-resolution Observations of the Low Atmospheric Response to Small Coronal Heating Events in an Active Region Core

The Astrophysical Journal, 2023
High-resolution spectral observations of the lower solar atmosphere (chromosphere and transition region) during coronal heating events, in combination with predictions from models of impulsively heated loops, provide powerful diagnostics of the ...
Paola Testa, Helle Bakke, Luc Rouppe van der Voort, Bart De Pontieu   +3 more
doaj   +1 more source

A Strong-flare Prediction Model Developed Using a Machine-learning Algorithm Based on the Video Data Sets of the Solar Magnetic Field of Active Regions

The Astrophysical Journal Supplement Series, 2023
It is well accepted that the physical properties obtained from the solar magnetic field observations of active regions (ARs) are related to solar eruptions.
Jingjing Wang, Bingxian Luo, Siqing Liu, Yue Zhang   +3 more
doaj   +1 more source

Information Horizon of Solar Active Regions

The Astrophysical Journal Letters, 2023
Information theory is used to characterize the solar active region periodicities and memories from the Carrington map images 1974–2021. The active regions typically evolve and move from one map to the next.
Jay R. Johnson, Simon Wing, Carson O’ffill, Bishwa Neupane   +3 more
doaj   +1 more source