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Solar flares emanate from solar active regions hosting complex and strong bipolar magnetic fluxes. Estimating the probability of an active region to flare and defining reliable precursors of intense flares is an extremely challenging task…

We present results of a global survey of single-pixel intensity power spectra from a 12-hour time period on 26 June 2013 in a 1600x1600 pixel region from four channels of the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly…

Solar and Stellar Astrophysics · Physics 2019-01-29 Karl Battams , Brendan M. Gallagher , Robert S. Weigel

Evidence for small amounts of very hot plasma has been found in active regions and might be the indication of an impulsive heating, released at spatial scales smaller than the cross section of a single loop. We investigate the heating and…

Solar and Stellar Astrophysics · Physics 2016-01-13 E. Tajfirouze , F. Reale , A. Petralia , P. Testa

Active learning is a promising alternative to alleviate the issue of high annotation cost in the computer vision tasks by consciously selecting more informative samples to label. Active learning for object detection is more challenging and…

Computer Vision and Pattern Recognition · Computer Science 2022-04-19 Jiaxi Wu , Jiaxin Chen , Di Huang

Studying the hemispheric distribution of active regions (ARs) with different magnetic morphology may clarify the features of the dynamo process that is hidden under the photospheric level. The magnetic flux data for 3047 ARs from the CrAO…

Solar and Stellar Astrophysics · Physics 2024-07-10 A. Zhukova

We compute a new generation of standard solar models (SSMs) that includes recent updates on some important nuclear reaction rates and a more consistent treatment of the equation of state. Models also include a novel and flexible treatment…

The Helioseismic Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) records line-of-sight Dopplergram images of convective flows on the surface. These images are used to obtain the multi-scale convective spectrum. We design…

Solar and Stellar Astrophysics · Physics 2021-08-09 Samarth G Kashyap , Shravan M Hanasoge

The coming years will see routine use of solar data of unprecedented spatial and spectral resolution, time cadence, and completeness in the wavelength domain. To capitalize on the soon to be available radio facilities such as the expanded…

Solar and Stellar Astrophysics · Physics 2015-05-20 Gregory D. Fleishman , Gelu M. Nita , Dale E. Gary

The recent analysis of observations taken with the EIS instrument on Hinode suggests that well constrained measurements of the temperature distribution in solar active regions can finally be made. Such measurements are critical for…

Solar and Stellar Astrophysics · Physics 2015-06-04 Harry P. Warren , Amy R. Winebarger , David H. Brooks

We explore the association of non-neutralized currents with solar flare occurrence in a sizable sample of observations, aiming to show the potential of such currents in solar flare prediction. We use the regularly produced high quality…

Solar and Stellar Astrophysics · Physics 2017-11-01 Ioannis Kontogiannis , Manolis K. Georgoulis , Sung-Hong Park , Jordan A. Guerra

In this paper a new technique for modeling non-linear force-free fields directly from line of sight magnetogram observations is presented. The technique uses sequences of magnetograms directly as lower boundary conditions to drive the…

Solar and Stellar Astrophysics · Physics 2011-02-28 Duncan H. Mackay , L. M. Green , Aad van Ballegooijen

The continuous observation of the magnetic field by Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI) produces numerous image sequences in time and space. These sequences provide data support for predicting the…

Solar and Stellar Astrophysics · Physics 2021-06-23 Liang Bai , Yi Bi , Bo Yang , Jun-Chao Hong , Zhe Xu , Zhen-Hong Shang , Hui Liu , Hai-Sheng Ji , Kai-Fan Ji

Previous solar observations have shown that coronal loops near 1 MK are difficult to reconcile with simple heating models. These loops have lifetimes that are long relative to a radiative cooling time, suggesting quasi-steady heating. The…

We compare the ability of 11 Differential Emission Measure (DEM) forward-fitting and inversion methods to constrain the properties of active regions and solar flares by simulating synthetic data using the instrumental response functions of…

Solar and Stellar Astrophysics · Physics 2016-04-13 M. J. Aschwanden , P. Boerner , A. Caspi , J. M. McTiernan , D. Ryan , H. P. Warren

Our knowledge of the low solar atmosphere, i.e., the photosphere and chromosphere, is based on the knowledge gained from the observations and the theoretical and numerical modeling of these layers. In this sense, the thermodynamical and…

Solar and Stellar Astrophysics · Physics 2024-03-12 Alberto Sainz Dalda , Aaryan Agrawal , Bart De Pontieu , M. Gosic

We present a new data product, called Space-Weather MDI Active Region Patches (SMARPs), derived from maps of the solar surface magnetic field taken by the Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory (SoHO).…

Solar and Stellar Astrophysics · Physics 2021-09-21 Monica G. Bobra , Paul J. Wright , Xudong Sun , Michael J. Turmon

The study of solar active regions (ARs) is of central importance to a range of fundamental science, as well as the practical applications of space weather. Active region emergence and life cycles are two areas of particular interest, yet…

Solar and Stellar Astrophysics · Physics 2025-10-30 Emily I. Mason , Kara L. Kniezewski

Context. Ubiquitous small-scale vortical motions are seen to occur in the solar atmosphere both in simulations and observations. They are thought to play a significant role in the local heating of the quiet chromosphere and corona. In a…

Solar and Stellar Astrophysics · Physics 2023-12-25 J. R. Canivete Cuissa , O. Steiner

Accurate measurements of magnetic and velocity fields in and around solar active regions are key to unlocking the mysteries of the formation and the decay of sunspots. High spatial resolution image and spectral sequences with a high cadence…

We propose a novel methodology to identity flows in the solar atmosphere and classify their velocities as either supersonic, subsonic, or sonic. The proposed methodology consists of three parts. First, an algorithm is applied to the Solar…

Solar and Stellar Astrophysics · Physics 2021-01-13 E. Philishvi , B. M. Shergelashvili , S. Buitendag , J. Raes , S. Poedts , M. L. Khodachenko