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We present an analysis of intermittent processes occurred during the impulsive phase of the flare SOL2012-03-13, using hard X-rays and submillimeter radio data. Intermittency is a key characteristic in turbulent plasmas and have been a…

Solar and Stellar Astrophysics · Physics 2016-06-22 C. Guillermo Giménez de Castro , Paulo J. A. Simões , Jean-Pierre Raulin , Odilon M. Guimarães

Solar flares are associated with intense soft X-ray emission generated by the hot flaring plasma. Kink unstable twisted flux-ropes provide a source of magnetic energy which can be released impulsively and account for the flare plasma…

Solar and Stellar Astrophysics · Physics 2015-03-25 R. F. Pinto , N. Vilmer , A. S. Brun

Three phases are typically observed during solar flares: the preflare, impulsive, and decay phases. During the impulsive phase, it is believed that the electrons and other particles are accelerated after the stored energy in the magnetic…

Solar and Stellar Astrophysics · Physics 2016-02-15 W. G. Fajardo-Mendieta , J. C. Martínez-Oliveros , J. D. Alvarado-Gómez , B. Calvo-Mozo

Coronae express different facets of their energy release processes in different wavelength regions. While soft X-ray and EUV emission dominates the radiative losses of the thermal plasma, hard X-ray emission (>10 keV) can be produced from…

Astrophysics · Physics 2007-05-23 Manuel Guedel

The temperature distribution of the emitting plasma is a crucial constraint when studying the heating of solar flare footpoints. However, determining this for impulsive phase footpoints has been difficult in the past due to insufficient…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. R. Graham , I. G. Hannah , L. Fletcher , R. O. Milligan

In this paper, we present the observations of two successive fast-mode extreme ultraviolet (EUV) wave events observed on 2016 July 23. Both fast-mode waves were observed by the Atmospheric Imaging Assembly (AIA) instrument on board the…

Solar and Stellar Astrophysics · Physics 2018-08-22 R. Chandra , P. F. Chen , R. Joshi , B. Joshi , B. Schmieder

On 10 March 2001 the active region NOAA 9368 produced an unusually impulsive solar flare in close proximity to the solar limb. This flare has previously been studied in great detail, with observations classifying it as a type 1 white-light…

Astrophysics · Physics 2009-11-13 J. C. Martinez-Oliveros , H. Moradi , A-C. Donea

A complete understanding of the onset and subsequent evolution of confined flares has not been achieved. Earlier studies mainly analyzed disk events so as to reveal their magnetic topology and cause of confinement. In this study, taking…

Solar and Stellar Astrophysics · Physics 2018-03-14 Hao Ning , Yao Chen , Zhao Wu , Yang Su , Hui Tian , Gang Li , Guohui Du , Hongqiang Song

Here we present the study of a compact emission source during an X1.3 flare on 2022-March-30. Within a $\sim41$~s period (17:34:48 UT to 17:35:29 UT), IRIS observations show spectral lines of Mg II, C II and Si IV with extremely broadened,…

Solar and Stellar Astrophysics · Physics 2023-09-13 Yan Xu , Graham S. Kerr , Vanessa Polito , Nengyi Huang , Ju Jing , Haimin Wang

The 2014 March 29 X1 solar flare (SOL20140329T17:48) produced bright continuum emission in the far- and near-ultraviolet (NUV) and highly asymmetric chromospheric emission lines, providing long-sought constraints on the heating mechanisms…

Solar and Stellar Astrophysics · Physics 2017-02-17 Adam F. Kowalski , Joel C. Allred , Adrian N. Daw , Gianna Cauzzi , Mats Carlsson

We present observations of a B7.9-class flare that occurred on the 24th January, 2015, using the Atmopsheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO), the EUV Imaging Spectrometer (EIS) and the X-Ray Telescope of…

Solar and Stellar Astrophysics · Physics 2017-03-29 Giuseppe Nisticò , Vanessa Polito , Valery M. Nakariakov , Giulio del Zanna

We have explored the relationship between hard X-ray (HXR) emissions and Doppler velocities caused by the chromospheric evaporation in two X1.6 class solar flares on 2014 September 10 and October 22, respectively. Both events display double…

Solar and Stellar Astrophysics · Physics 2015-11-04 Dong Li , Zongjun Ning , Qingmin Zhang

Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed…

Solar and Stellar Astrophysics · Physics 2015-11-04 X. Fang , D. Yuan , T. Van Doorsselaere , R. Keppens , C. Xia

The aim of the thesis is the study of properties of solar flares via reconstruction of energy distributions of accelerated/heated electrons, diagnostics of flare plasma based on EUV and X-ray observations, as well as the estimation of the…

Solar and Stellar Astrophysics · Physics 2017-10-31 Galina G. Motorina

We model in detail a flare observed on Proxima Centauri with the EPIC-PN on board XMM-Newton at high statistics and high time resolution and coverage. Time-dependent hydrodynamic loop modeling is used to describe the rise and peak of the…

Astrophysics · Physics 2009-11-10 F. Reale , M. Guedel , G. Peres , M. Audard

The recent discovery of impulsive solar burst emission in the 30 THz band is raising new interpretation challenges. One event associated with a GOES M2 class flare has been observed simultaneously in microwaves, H-alpha, EUV, and soft X-ray…

Before the onset of a flare is observed in hard X-rays there is often a prolonged pre-flare or pre-heating phase with no detectable hard X-ray emission but pronounced soft X-ray emission suggesting that energy is being released and…

Solar and Stellar Astrophysics · Physics 2015-06-19 Marina Battaglia , Lyndsay Fletcher , Paulo J. A. Simões

Abridged. We observed the 40 Myr old star DS Tuc A with XMM-Newton and recorded two X-ray bright flares, with the second event occurring about 12 ks after the first one. Their duration from the rise to the end of the decay was of about 8-10…

Solar and Stellar Astrophysics · Physics 2022-10-26 I. Pillitteri , C. Argiroffi , A. Maggio , G. Micela , S. Benatti , F. Reale , S. Colombo , S. J. Wolk

Svestka (Solar Phys. 1989, 121, 399) on the basis of the Solar Maximum Mission observations introduced a new class of flares, the so-called flare hybrids. When they start, they look as typical compact flares (phase 1), but later on they…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. Tomczak , P. Dubieniecki

Images of an east-limb flare on 3 November 2010 taken in the 131 \AA\ channel of the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory provide a convincing example of a long current sheet below an erupting plasmoid, as…

Solar and Stellar Astrophysics · Physics 2015-06-16 Pankaj Kumar , D. E. Innes