Structure and physical conditions in the Hα loops of an M7.7 solar flare

Firstova, N. M.; Polyakov, V. I.

doi:10.1134/s1063773717110032

Cited by 3 publications

(3 citation statements)

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“…In the case of proton beams, this occurs at 400 keV; and in the case of electron beams, at 200 eV. Firstova [2015] continued studying the 2002 July 23 flare, using RHESSI observations of X-rays and γ radiation [Lin et al, 2003]. The author compared LSVT high-resolution spectropolarimetric data with RHESSI data.…”

Section: Main Results Of Studies Made With Lsvtmentioning

confidence: 99%

“…An interesting object to study was the limb system of flare loops emerging after the M7.7 Masuda flare, which began on July 19, 2012 at 04:17 UT. The loops were observed with LSVT in the active region (AR) NOAA 11520 on the southwest solar limb [Firstova, Polyakov, 2017]. The time interval of these observations was 06:54-07:40 UT.…”

Section: Main Results Of Studies Made With Lsvtmentioning

confidence: 99%

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Solar activity research at the Baikal Astrophysical Observatory of ISTP SB RAS

Borovik¹,

Головко²,

Golovko

et al. 2019

Solar-Terrestrial Physics

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The article presents the main results of solar studies carried out at the Baikal Astrophysical Observatory (BAO) of the Institute of Solar-Terrestrial Physics SB RAS (ISTP SB RAS) for 40 years. It outlines the history of BAO and lists its telescopes. Much attention is given to the Large Solar Vacuum Telescope (LSVT) designed to observe solar formations with high spatial and spectral resolution. Technical parameters of this instrument are specified along with some results of the studies carried out with it. Information about the full-disk chromospheric telescope and scientific problems solved with it is represented together with the basic scientific results. The telescope is used to study solar activity complexes and solar flares. References to the basic publications that have used BAO results are presented.

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Section: Main Results Of Studies Made With Lsvtmentioning

confidence: 99%

Section: Main Results Of Studies Made With Lsvtmentioning

confidence: 99%

Solar activity research at the Baikal Astrophysical Observatory of ISTP SB RAS

Borovik¹,

Головко²,

Golovko

et al. 2019

Solar-Terrestrial Physics

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“…A 1D radiation-hydrodynamic model of flare loops by Tsiklauri et al (2004), based on the Bastille-Day flare of 2000 July 14, shows that flare loop densities up to 5 × 10 11 cm −3 can be achieved (Aschwanden 2005, Chapter 16). Recently, Firstova & Polyakov (2017) analyzed Hα spectral measurements of off-limb M7.7-class flare loops, finding electron densities of 10 11 cm −3 . This paper presents an analysis of high-resolution imaging spectroscopy data of off-limb cool loops of the X8.2-class flare acquired by the Swedish 1-m Solar Telescope (SST; Scharmer et al 2003a,b).…”

Section: Introductionmentioning

confidence: 99%

Spectral Diagnostics of Cool Flare Loops Observed by the SST. I. Inversion of the Ca ii 8542 Å and Hβ Lines

Koza

Kuridze

Heinzel

et al. 2019

ApJ

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Flare loops form an integral part of eruptive events, being detected in the range of temperatures from X-rays down to cool chromospheric-like plasmas. While the hot loops are routinely observed by the Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA), cool loops seen off-limb are rare. In this paper we employ unique observations of the SOL2017-09-10T16:06 X8.2-class flare which produced an extended arcade of loops. The Swedish 1-m Solar Telescope (SST) made a series of spectral images of the cool off-limb loops in the Ca ii 8542Å and the hydrogen Hβ lines. Our focus is on the loop apices. Non-LTE spectral inversion is achieved through the construction of extended grids of models covering a realistic range of plasma parameters. The Multilevel Accelerated Lambda Iterations (MALI) code solves the non-LTE radiative-transfer problem in a 1D externally-illuminated slab, approximating the studied loop segment. Inversion of the Ca ii 8542Å and Hβ lines yields two similar solutions, both indicating high electron densities around 2 × 10 12 cm −3 and relatively large microturbulence around 25 km s −1 . These are in reasonable agreement with other independent studies of the same or similar events. In particular, the high electron densities in the range 10 12 −10 13 cm −3 are consistent with those derived from the SDO's Helioseismic and Magnetic Imager white-light observations. The presence of such high densities in solar eruptive flares supports the loop interpretation of the optical continuum emission of stars which manifest superflares.

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