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Based on a sample of 1114 flares observed simultaneously in hard X-rays (HXR) by the BATSE instrument and in soft X-rays (SXR) by GOES, we studied several aspects of the Neupert effect and its interpretation in the frame of the…

Astrophysics · Physics 2009-11-07 A. Veronig , B. Vrsnak , B. R. Dennis , M. Temmer , A. Hanslmeier , J. Magdalenic

Acceleration of particles and plasma heating is one of the fundamental problems in solar flare physics. An accurate determination of the spectrum of flare energized electrons over a broad energy range is crucial for our understanding of…

Solar and Stellar Astrophysics · Physics 2015-12-16 Marina Battaglia , Galina Motorina , Eduard P. Kontar

We report observations of an X class flare on 2011 September 6 by the instruments onboard the Solar Dynamics Observatory (SDO). The flare occurs in a complex active region with multiple polarities. The Extreme-Ultraviolet (EUV) Variability…

Solar and Stellar Astrophysics · Physics 2015-06-16 Y. Dai , M. D. Ding , Y. Guo

The current sheet is an essential feature in solar flares and is the primary site for magnetic reconnetion and energy release. Imaging observations feature a long linear structure above the candle-flame-shaped flare loops, which resembles…

Solar and Stellar Astrophysics · Physics 2024-07-03 Tingyu Gou , Katharine K. Reeves

We observed the TeV blazar 1ES 1218+304 with the X-ray astronomy satellite Suzaku in May 2006. At the beginning of the two-day continuous observation, we detected a large flare in which the 5-10 keV flux changed by a factor of ~2 on a…

Astrophysics · Physics 2009-06-23 R. Sato , J. Kataoka , T. Takahashi , G. M. Madejski , S. Rugamer , S. J. Wagner

New calculations of radiative rates and electron impact excitation cross sections for Fe XI are used to derive emission line intensity ratios involving 3s^23p^4 - 3s^23p^33d transitions in the 180-223 A wavelength range. These ratios are…

We use more than 4,500 microflares from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) microflare data set (Christe et al., 2008, Ap. J., 677, 1385) to estimate electron densities and volumetric filling factors of…

Solar and Stellar Astrophysics · Physics 2011-07-21 R. N. Baylor , P. A. Cassak , S. Christe , I. G. Hannah , Säm Krucker , D. J. Mullan , M. A. Shay , H. S. Hudson , R. P. Lin

Extreme scattering events (ESEs) are observed as dramatic ($>50\%$) drops in flux density that occur over an extended period of weeks to months. Discrete plasma lensing structures are theorized to scatter the radio waves produced by distant…

Astrophysics of Galaxies · Physics 2024-01-19 Kelvin Au , Jason D. Fiege , Adam Rogers

We present an assessment of the accuracy of the calibration measurements and atomic physics models that go into calculating the SDO/AIA response as a function of wavelength and temperature. The wavelength response is tested by convolving…

Solar and Stellar Astrophysics · Physics 2015-06-16 P. Boerner , P. Testa , H. Warren , M. A. Weber , C. J. Schrijver

This work aims to characterize precisely and systematically the non-thermal characteristics of the electron Velocity Distribution Function (eVDF) in the solar wind at 1 au using data from the Wind spacecraft. We present a comprehensive…

Space Physics · Physics 2023-07-26 Chadi S. Salem , Marc Pulupa , Stuart D. Bale , Daniel Verscharen

The new generation of lithography tools use high energy EUV radiation which ionizes the present background gas due to photoionization. To predict and understand the long term impact on the highly delicate mirrors It is essential to…

Plasma Physics · Physics 2015-07-07 R. M. van der Horst , J. Beckers , E. A. Osorio , V. Y. Banine

Large solar eruptive events, including solar flares and coronal mass ejections (CMEs), can lead to solar energetic particle (SEP) events. During these events, protons are accelerated up to several GeV and pose numerous space weather risks.…

Solar and Stellar Astrophysics · Physics 2023-03-08 Charlotte Waterfall , Silvia Dalla , Osku Raukunen , Daniel Heynderickx , Piers Jiggens , Rami Vainio

The study of the solar energetic particle events (SEPs) and their association with solar flares and other activities are very crucial to understand the space weather. Keeping this in view, in this paper, we present the study of the SEPs…

Solar and Stellar Astrophysics · Physics 2021-02-17 Raj Kumar , Ramesh Chandra , Bimal Pande , Seema Pande

EUVE satellite spectroscopic observations (SW, MW and LW bands covering 80 - 160, 170 - 350 and 450 A with resolutions 0.5, 1 and 2 A) and photometric observations (Deep Sky Survey, broad-band 70 - 140 A) have been obtained for two contact,…

Astrophysics · Physics 2016-08-30 Slavek M. Rucinski

Solar flare electron acceleration is an efficient process, but its properties (mechanism, location) are not well constrained. Via hard X-ray (HXR) emission, we routinely observe energetic electrons at the Sun, and sometimes we detect…

Solar and Stellar Astrophysics · Physics 2023-10-09 Ross Pallister , Natasha L. S. Jeffrey

Flare-driven coronal rain can manifest from rapidly cooled plasma condensations near coronal loop-tops in thermally unstable post-flare arcades. We detect 5 phases that characterise the post-flare decay: heating, evaporation, conductive…

Solar and Stellar Astrophysics · Physics 2016-12-21 E. Scullion , L. Rouppe Van Der Voort , P. Antolin , S. Wedemeyer , G. Vissers , E. P. Kontar , P. Gallagher

Time integrated spectroscopic measurements are carried out to characterize transient plasma stream produced in a coaxial pulsed plasma accelerator. This method allows the estimation of different plasma parameters and its evolution with…

Plasma Physics · Physics 2020-08-04 A. Ahmed , S. Singha , S. Borthakur , N. K. Neog , T. K. Borthakur , J. Ghosh

The extreme ultraviolet (XUV) emission from dense plasmas generated with sub-10-fs laser pulses with varying peak intensities up to 3*10^16 W/cm^2 is investigated for different target materials. K shell spectra are obtained from low Z…

Plasma Physics · Physics 2009-11-13 J. Osterholz , F. Brandl , M. Cerchez , T. Fischer , D. Hemmers , B. Hidding , A. Pipahl , G. Pretzler , S. J. Rose , O. Willi

Solar flares release magnetic energy through reconnection, accelerating electrons into nonthermal velocity distributions, including crescent-shaped electron populations. These energetic electron distributions are crucial in driving…

Solar and Stellar Astrophysics · Physics 2025-01-08 Mehdi Yousefzadeh

We investigate the X-ray and UV emission detected by RHESSI and TRACE in the context of a solar flare on the 16th November 2002 with the goal of better understanding the evolution of the flare. We analysed the characteristics of the X-ray…

Solar and Stellar Astrophysics · Physics 2015-06-11 Hamish A. S. Reid , Nicole Vilmer , Guillaume Aulanier , Etienne Pariat