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Spectroscopic observations covering the wavelength range 3600--4600\AA are presented for a large flare on the late type M dwarf AT Mic (dM4.5e). A procedure to estimate the physical parameters of the flaring plasma has been used which…

The energy released in a solar flare is partitioned between thermal and non-thermal particle energy and lost to thermal conduction and radiation over a broad range of wavelengths. It is difficult to determine the conductive losses and the…

Astrophysics · Physics 2011-02-11 J. C. Raymond , G. Holman , A. Ciaravella , A. Panasyuk , Y. -K. Ko , J. Kohl

New laboratory measurements using an Electron Beam Ion Trap (EBIT) and an x-ray microcalorimeter are presented for the n=3 to n=2 Fe XVII emission lines in the 15 {\AA} to 17 {\AA} range, along with new theoretical predictions for a variety…

Instrumentation and Methods for Astrophysics · Physics 2011-06-15 J. D. Gillaspy , T. Lin , L. Tedesco , J. N. Tan , J. M. Pomeroy , J. M. Laming , N. Brickhouse , G. -X. Chen , E. Silver

The radio complex Sgr B region is observed with the X-Ray Imaging Spectrometers (XIS) on board Suzaku. This region exhibits diffuse iron lines at 6.4, 6.7 and 6.9 keV, which are K$\alpha$ lines of Fe \emissiontype{I} (neutral iron),…

We report the diffuse X-ray emissions from the Sgr A and B regions observed with Suzaku. From the Sgr A region, we found many K-shell transition lines of iron and nickel. The brightest are K alpha lines from FeI, FeXXV and FeXXVI at 6.4…

Astrophysics · Physics 2008-11-26 Katsuji Koyama , Yoshiaki Hyodo , Tatsuya Inui

The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft observed flare footpoint regions coincident with a surge for a M3.7 flare observed on 25 September 2011 at N12 E33 in active region 11302. The flare was observed in…

Solar and Stellar Astrophysics · Physics 2015-10-30 George A. Doschek , Harry P. Warren , Brian R. Dennis , Jeffrey W. Reep , Amir Caspi

The relative amount of high temperature plasma has been found to be a useful diagnostic to determine the frequency of coronal heating on sub-resolution structures. When the loops are infrequently heated, a broad emission measure (EM) over a…

Many energy levels of singly ionised iron (Fe II, $Z=26$) remain uncertain or experimentally unknown. Their identification and spectral line data are required in reliable astrophysical spectral analyses. In motivation for improving the…

Atomic Physics · Physics 2024-08-16 M. Ding , H. Kozuki , F. Concepcion , G. Nave , J. C. Pickering

The hydrogen Lyman lines provide important diagnostic information about the dynamics of the chromosphere, but there have been few systematic studies of their variability during flares. We investigate Doppler shifts in these lines in several…

Solar and Stellar Astrophysics · Physics 2016-11-30 Stephen A Brown , Lyndsay Fletcher , Nicolas Labrosse

Solar flares are complex phenomena emitting all types of electromagnetic radiation, and accelerating particles on timescales of minutes, converting magnetic energy to thermal, radiative, and kinetic energy through magnetic reconnections. As…

Solar and Stellar Astrophysics · Physics 2023-09-01 Crisel Suarez , Christopher S. Moore

In this study, we investigate motions in the hot plasma above the flare loops during the 2017 September 10 X8.2 flare event. We examine the region to the south of the main flare arcade, where there is data from the Interface Region Imaging…

Solar and Stellar Astrophysics · Physics 2021-01-06 Katharine K. Reeves , Vanessa Polito , Bin Chen , Giselle Galan , Sijie Yu , Wei Liu , Gang Li

The infrared Mg I lines near 12 microns are a pair of emission lines which are magnetically sensitive and have been used to measure solar magnetic fields. Here we calculate the response of the Mg I 12.32 $\mu$m line during a flare and find…

Solar and Stellar Astrophysics · Physics 2020-08-04 Jie Hong , Xianyong Bai , Ying Li , M. D. Ding , Yuanyong Deng

We present Extreme Ultraviolet Explorer spectroscopy and photometry of the nearby F8 V star HD 35850 (HR 1817). The EUVE spectra reveal 28 emission lines from Fe IX and Fe XV to Fe XXIV. The Fe XXI 102, 129 A ratio yields an upper limit for…

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

Large solar flares occasionally trigger significant space-weather disturbances that affect the technological infrastructures of modern civilization, and therefore require further investigation. Although these solar flares have been…

Solar and Stellar Astrophysics · Physics 2023-10-06 Keitarou Matsumoto , Satoshi Masuda , Masumi Shimojo , Hisashi Hayakawa

Using the Livermore X-ray Spectral Synthesizer, which calculates spectral models of highly charged ions based primarily on HULLAC atomic data, we investigate the temperature, density, and photoexcitation dependence of the I(11.92 A)/I(11.77…

Astrophysics · Physics 2009-11-07 Christopher W. Mauche , Duane A. Liedahl , Kevin B. Fournier

Ground- and space-based observations of solar flares from radio wavelengths to gamma-rays have produced considerable insights but raised several unsolved controversies. The last unexplored wavelength frontier for solar flares is in the…

Ion energy measurements have been made in the scrape off layer of the Mega Amp Spherical Tokamak (MAST) using a midplane retarding field energy analyser (RFEA) in H-mode plasmas during the inter-edge localised mode (ELM) period and during…

Plasma Physics · Physics 2013-06-28 S. Y. Allan , S. Elmore , A. Kirk , M. Kočan , P. Tamain

The degree of linear polarization in solar flares has not yet been precisely determined despite multiple attempts to measure it with different missions. The high energy range in particular has very rarely been explored, due to its greater…

Astrophysics · Physics 2009-11-11 E. Suarez-Garcia , W. Hajdas , C. Wigger , K. Arzner , M. Guedel , A. Zehnder , P. Grigis

Extreme ultraviolet (EUV) spectra emitted from aluminum in the 5-340 A wavelength range were observed in Experimental Advanced Superconducting Tokamak (EAST) discharges. Several spectral lines from aluminum ions with different degrees of…