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Related papers: Differential Emission Measure Evolution as a Precu…

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In a previous paper we have described a technique to derive constraints on the differential emission measure (DEM) distribution, a measure of the temperature distribution, of collisionally ionized hot plasmas from their X-ray emission line…

Astrophysics · Physics 2009-11-10 Patrick S. Wojdowski , Norbert S. Schulz

We investigated if signatures of coronal mass ejections (CMEs) can be retrieved in the differential emission measure (DEM) from Sun-as-a-star extreme-ultraviolet (EUV) observations. We analyzed 16 major, eruptive (i.e., associated with…

Solar and Stellar Astrophysics · Physics 2026-05-05 Angelos Michailidis , Spiros Patsourakos

Of all the activity observed on the Sun, two of the most energetic events are flares and Coronal Mass Ejections (CMEs). Usually, solar active regions that produce large flares will also produce a CME, but this is not always true (Yashiro et…

Solar and Stellar Astrophysics · Physics 2016-04-25 Monica G. Bobra , Stathis Ilonidis

In our previous paper, we have presented a theory to explain the observed universal correlation between the emission measure ($EM=n^2 V$) and temperature (T) for solar/stellar flares on the basis of the magnetic reconnection model with heat…

Astrophysics · Physics 2016-08-30 Kazunari Shibata , Takaaki Yokoyama

Solar active regions and the processes that occur in them have been extensively studied and analyzed and many types of models and characterizations have been proposed for the occurrence of different eruptive events that take place in the…

Solar and Stellar Astrophysics · Physics 2020-12-09 N. Granados Hernández , S. Vargas Domínguez

The light curves of solar flares in the impulsive phase are complex in general, indicating that multiple physical processes are involved in. With the GOES (Geostationary Operational Environmental Satellite) observations, we find that there…

Solar and Stellar Astrophysics · Physics 2015-06-16 HAN , Fei-ran , LIU , Si-ming

Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim to understand the magnetic properties that govern such flares and eruptions, we systematically survey all flare…

Solar and Stellar Astrophysics · Physics 2017-01-11 Shin Toriumi , Carolus J. Schrijver , Louise K. Harra , Hugh Hudson , Kaori Nagashima

We report solar flare plasma to be multi-thermal in nature based on the theoretical model and study of the energy-dependent timing of thermal emission in ten M-class flares. We employ high-resolution X-ray spectra observed by the Si…

Solar and Stellar Astrophysics · Physics 2011-03-30 Rajmal Jain , Arun Kumar Awasthi , Arvind Singh Rajpurohit , Markus J. Aschwanden

We present a new method for performing differential emission measure (DEM) inversions on narrow-band EUV images from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The method yields positive definite…

Solar and Stellar Astrophysics · Physics 2015-07-15 Mark C. M. Cheung , P. Boerner , C. J. Schrijver , P. Testa , F. Chen , H. Peter , A. Malanushenko

The Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamics Observatory (SDO) provides coronal EUV imaging over a broader temperature sensitivity range than the previous generations of instruments (EUVI, EIT, and TRACE).…

Solar and Stellar Astrophysics · Physics 2015-10-07 Federico A. Nuevo , Alberto M. Vásquez , Enrico Landi , Richard Frazin

The reconstruction of the differential emission measure (DEM) from observations of spectral line intensities provides information on the temperature distribution of the emission measure in the region observed. The inversion process is known…

Solar and Stellar Astrophysics · Physics 2022-05-18 Kenneth P. Dere

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

Ways to give medium- and short-term predictions of solar flares are proposed according to the statistical analysis of events during solar cycle 23. On one hand, the time distribution of both C and M class flares shows two main periods of…

Astrophysics · Physics 2008-11-17 Z. Q. Qu

The detailed knowledge of plasma heating and acceleration region properties presents a major observational challenge in solar flare physics. Using the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), the high temperature differential…

Solar and Stellar Astrophysics · Physics 2015-12-02 Natasha Jeffrey , Eduard Kontar , Brian Dennis

Thermal changes in coronal loops are well-studied, both in quiescent active regions and in flaring scenarios. However, relatively little attention has been paid to loop emission in the hours before the onset of a solar flare; here, we…

Solar and Stellar Astrophysics · Physics 2024-11-20 Kara L. Kniezewski , Emily I. Mason , Vadim M. Uritsky , Seth H. Garland

Observational pre-cursors of large solar flares provide a basis for future operational systems for forecasting. Here, we study the evolution of the normalized emergence (EM), shearing (SH) and total (T) magnetic helicity flux components for…

Solar and Stellar Astrophysics · Physics 2022-02-09 Sz. Soós , M. B. Korsós , H. Morgan , R. Erdélyi

There is a wide range of eruptions in the solar atmosphere which contribute to space weather, including the major explosions of radiation known as flares. To examine pre-event behavior in delta-spot regions, we use here a method based on…

Solar and Stellar Astrophysics · Physics 2019-01-21 Marianna B. Korsos , Shuhong Yang , Robert Erdelyi

Solar flares are intense bursts of electromagnetic radiation, which occur due to a rapid destabilization and reconnection of the magnetic field. While pre-flare signatures and trends have been investigated from magnetic observations prior…

Solar and Stellar Astrophysics · Physics 2025-06-18 Kara L. Kniezewski , Emily I. Mason , Daniel J. Emmons , Kyle E. Fitch , Seth H. Garland

With machine learning entering into the awareness of the heliophysics community, solar flare prediction has become a topic of increased interest. Although machine learning models have advanced with each successive publication, the input…

Solar and Stellar Astrophysics · Physics 2020-03-11 Brandon Panos , Lucia Kleint

One of the defining characteristics of a solar flare is the impulsive formation of very high temperature plasma. The properties of the thermal emission are not well understood, however, and the analysis of solar flare observations is often…

Solar and Stellar Astrophysics · Physics 2015-06-12 Harry P. Warren , John T. Mariska , George A. Doschek