Onset of Photospheric Impacts and Helioseismic Waves in X9.3 Solar Flare of 2017 September 6

Sharykin, I. N.; Kosovichev, A. G.

doi:10.3847/1538-4357/aad558

Cited by 30 publications

(22 citation statements)

References 37 publications

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“…On the 6 September 2017 the active region NOAA 12673 produced two X-class flares: an X2.2 flare and three hours later an X9.3 flare that have been studied by many au-Send offprint requests to: v.zharkova e-mail: valentina.zharkova@northumbria.ac.uk thors. A few sunquakes and magneto-acoustic waves associated with the X9.3 flare were originally reported by Sharykin & Kosovichev (2018); Zhao & Chen (2018). The X9.3 flare of 6 September 2017 was explored in our paper, part 1 (Zharkov et al 2020, thereafter paper 1) presenting the available observations of gamma-ray (GR), hard X-ray (HXR), extra ultraviolate (EUV), Hα and white light emission combined with four (possibly five) sunquakes detected by the Helioseismic and Magnetic Imager (HMI) aboard Solar Dynamic Observatory (SDO) (Scherrer et al 2012).…”

Section: Introductionmentioning

confidence: 91%

Sunquake with a second bounce, other sunquakes, and emission associated with the X9.3 flare of 6 September 2017

Zharkova

Zharkov

Druett

et al. 2020

A&A

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In this paper we present the interpretation of the observations of the flare from 6 September 2017 reported in Paper I. These include gamma-ray (GR), hard X-ray (HXR), soft X-rays, Lyα line, extreme ultraviolet (EUV), Hα, and white light (WL) emission, which were recorded during the two flaring events 1 (FE1) and 2 (FE2) that occurred at 11:55:37 UT (FE1) and 12:06:40 UT (FE2). Paper I also reported the first detection of the sunquake with first and second bounces of seismic waves combined with four other sunquakes in different locations supported with the observations of HXR, GR, EUV, Hα, and WL emission with strongly varying spatial resolution and temporal coverage. In the current paper, we propose some likely scenarios for heating of flaring atmospheres in the footpoints with sunquakes which were supported with EUV and Hα emission. We used a range of parameters derived from the HXR, EUV, and Hα line observations to generate hydrodynamic models, which can account for the blueshifts derived from the EUV emission and the redshifts observed with the EUV Imaging Spectrometer in the He II line and by the CRisp Imaging Spectro-Polarimeter in the Swedish Solar Telescope in Hα line emission. The parameters of hydrodynamic shocks produced by different beams in flaring atmospheres were used as the initial conditions for another type of hydrodynamic models that were developed for acoustic wave propagation in the solar interior. These models simulate the sets of acoustic waves produced in the interior by the hydrodynamic shocks from atmospheres above deposited in different footpoints of magnetic loops. The Hα line profiles with large redshifts in three kernels (two in FE1 and one in FE2) were interpreted with the full non-local thermodynamic equilibrium radiative simulations in all optically thick transitions (Lyman lines and continuum Hα, Hβ, and Pα) applied for flaring atmospheres with fast downward motions while considering thermal and non-thermal excitation and ionisation of hydrogen atoms by energetic power-law electron beams. The observed Hα line profiles in three kernels were fit with the simulate blue wing emission of the Hα line profiles shifted significantly (by 4–6 Å) towards the line red wings, because of strong downward motions with velocities about 300 km s−1 by the shocks generated in flaring atmospheres by powerful beams. The flaring atmosphere associated with the largest sunquake (seismic source 2 in FE1) is found consistent with being induced by a strong hydrodynamic shock produced by a mixed beam deposited at an angle of −30° from the local vertical. We explain the occurrence of a second bounce in the largest sunquake by a stronger momentum delivered by the shock generated in the flaring atmosphere by a mixed beam and deeper depths of the interior where this shock was deposited. Indeed, the shock with mixed beam parameters is found deposited deeply into the interior beneath the flaring atmosphere under the angle to the local vertical that would allow the acoustic waves generated in the direction closer to the surface to conserve enough energy for the second bounces from the interior layers and from the photosphere. The wave characteristics of seismic sources 1 and 3 (in FE1) were consistent with those produced by the shocks generated by similar mixed beams deposited at the angles −(0 − 10)° (seismic source 1) and +30° (seismic source 3) to the local vertical. The differences of seismic signatures produced in the flares of 6 September 2011 and 2017 are also discussed.

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Section: Introductionmentioning

confidence: 91%

Sunquake with a second bounce, other sunquakes, and emission associated with the X9.3 flare of 6 September 2017

Zharkova

Zharkov

Druett

et al. 2020

A&A

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“…The early September 2017 solar events were well‐observed by several space‐ and ground‐based instruments, receiving noteworthy attention by a number of papers in the literature (see, e.g., Chertok, ; Gary et al, ; Gopalswamy et al, ; Guo et al, ; Long et al, ; Luhmann et al, ; Omodei et al, ; Seaton & Darnel, ; Sharykin & Kosovichev, ; Shen et al, ; Sun & Norton, ; Warren et al, ). In this work we focus on the SEP events that accompany these eruptions, taking advantage of multispacecraft data from the Advanced Composition Explorer (ACE) and the Geostationary Operational Environmental Satellites (GOES) to provide an assessment of the SEP spectral shapes over a complete range of energies spanning from few hundreds of keV to a few GeV.…”

Section: Introductionmentioning

confidence: 99%

Spectral Analysis of the September 2017 Solar Energetic Particle Events

et al. 2019

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An interval of exceptional solar activity was registered in early September 2017, late in the decay phase of solar cycle 24, involving the complex Active Region 12673 as it rotated across the western hemisphere with respect to Earth. A large number of eruptions occurred between 4 and 10 September, including four associated with X-class flares. The X9.3 flare on 6 September and the X8.2 flare on 10 September are currently the two largest during cycle 24. Both were accompanied by fast coronal mass ejections and gave rise to solar energetic particle (SEP) events measured by near-Earth spacecraft. In particular, the partially occulted solar event on 10 September triggered a ground-level enhancement (GLE), the second GLE of cycle 24. A further, much less energetic SEP event was recorded on 4 September. In this work we analyze observations by the Advanced Composition Explorer (ACE) and the Geostationary Operational Environmental Satellites (GOES), estimating the SEP event-integrated spectra above 300 keV and carrying out a detailed study of the spectral shape temporal evolution. Derived spectra are characterized by a low-energy break at few/tens of MeV; the 10 September event spectrum, extending up to ∼1 GeV, exhibits an additional rollover at several hundred MeV. We discuss the spectral interpretation in the scenario of shock acceleration and in terms of other important external influences related to interplanetary transport and magnetic connectivity, taking advantage of multipoint observations from the Solar Terrestrial Relations Observatory. Spectral results are also compared with those obtained for the 17 May 2012 GLE event.

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“…Планируется исследовать предвспышечные магнитограммы для выбранных событий июля 1996 и декабря 2006 гг. по аналогии с тем, как было сделано другими авторами [7] для вспышки 06.09.2017 для исследования конфигурации магнитного поля; построить 3D модели вспышек с помощью GX симулятора [8] для рассмотренных трех событий; выявить общие и различающиеся от цикла к циклу черты мощных вспышек в минимуме солнечной активности.…”

Section: обсуждение результатов и выводыunclassified

Multiwavelength Study of Powerful Solar Flares at Minimum of 22, 23 and 24 Solar Cycles

Motorina¹,

Lysenko²,

Fleishman³

2018

Proceedings of the 22nd All-Russia Conference on Solar and Solar-Terrestrial Physics

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Onset of Photospheric Impacts and Helioseismic Waves in X9.3 Solar Flare of 2017 September 6

Cited by 30 publications

References 37 publications

Sunquake with a second bounce, other sunquakes, and emission associated with the X9.3 flare of 6 September 2017

Sunquake with a second bounce, other sunquakes, and emission associated with the X9.3 flare of 6 September 2017

Spectral Analysis of the September 2017 Solar Energetic Particle Events

Multiwavelength Study of Powerful Solar Flares at Minimum of 22, 23 and 24 Solar Cycles

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