Ultraviolet, hard X-ray, and gamma-ray emission of solar flares recorded by VUSS-L and SONG instruments in 2001–2003

Nusinov, A. A.; Kazachevskaya, T. V.; Kuznetsov, S. N.; Myagkova, I. N.; Yushkov, B. Yu.

doi:10.1134/s0038094606040034

Cited by 17 publications

(12 citation statements)

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“…Another enigma is the lack of detected hard X-ray flare ribbons which are expected to trace out the UV ribbons, since both emissions are excited by nonthermal electrons of similar energy in the chromosphere, and both emissions vary in a synchronized way as confirmed with the VUSS-L and SONG instruments onboard CORONAS-F (Nusinov et al 2006). One interpretation was the disparity of spatial scales of interacting flux systems during separator reconnection, where the compact loops are more conducive to produce hard X-rays, while the footpoints of the more extended loops mark the UV double ribbons (Alexander and Coyner 2006).…”

Section: Rhessi Observationsmentioning

confidence: 87%

Astrophysics in 2006

2007

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The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the universe) and others of which there are always many, like meteors and molecules, black holes and binaries.Comment: 244 pages, no figure

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Section: Rhessi Observationsmentioning

confidence: 87%

Astrophysics in 2006

2007

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“…The impulsive-phase peak (i.e., main peak for type I flares and sub-peak for type III flares) of Lyα basically holds the Neupert effect, which suggests that this kind of emission is closely related to the nonthermal electron beams (Nusinov et al 2006;Rubio da Costa et al 2009;Milligan & Chamberlin 2016). It is known that in the standard flare model, the electron beams deposit their energy mostly in the chromosphere via Coulomb collisions, where the Lyα line is mainly formed.…”

Section: Summary and Interpretationmentioning

confidence: 94%

“…In addition, there were some studies focusing on the relationship of the Lyα emission with soft X-ray (SXR) and hard X-ray (HXR) emissions. Nusinov et al (2006) reported that the Lyα maximum is reached well before the SXR maximum and the variation of the Lyα emission is synchronous with that of the HXR emission above 50 keV during the impulsive phase of a flare. These "Neupert-effect" features were also observed and confirmed by some other authors via studying different flare events (Rubio da Costa et al 2009;Milligan & Chamberlin 2016;Milligan et al 2017;Dominique et al 2018;Chamberlin et al 2018).…”

Section: Introductionmentioning

confidence: 96%

The Lyman-alpha Emission in Solar Flares. I. a Statistical Study on Its Relationship with the 1--8 Å Soft X-ray Emission

Jing,

Pan,

Yang

et al. 2020

Preprint

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We statistically study the relationship between the Lyman-alpha (Lyα) and 1-8 Å soft X-ray (SXR) emissions from 658 M-and X-class solar flares observed by the Geostationary Operational Environmental Satellite during 2006-2016. Based on the peak times of the two waveband emissions, we divide the flares into three types. Type I (III) has an earlier (a later) peak time in the Lyα emission than that in the SXR emission, while type II has nearly a same peak time (within the time resolution of 10 s) between the Lyα and SXR emissions. In these 658 flares, we find that there are 505 (76.8%) type I flares, 10 (1.5%) type II flares, and 143 (21.7%) type III flares, and that the three types appear to have no dependence on the flare duration, flare location, or solar cycle. Besides the main peak, the Lyα emission of the three type flares also shows sub-peaks which can appear in the impulsive or gradual phase of the flare. It is found that the main-peak (for type I) and sub-peak (for type III) emissions of Lyα that appear in the impulsive phase follow the Neupert effect in general. This indicates that such Lyα emissions are related to the nonthermal electron beam heating. While the main-peak (for type III) and sub-peak (for type I) emissions of Lyα that appear in the gradual phase are supposed to be primarily contributed by the thermal plasma that cools down.

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“…The hydrogen Balmer continuum enhancement at MUV wavelengths around 2000 Å was found to be highly synchronous with the enhancement of Lyα emission during a powerful solar flare (Dominique et al 2018), while the flare radiation in the Lyα and HXR ranges were demonstrated to have a close relationship (Nusinov et al 2006;Jing et al 2020;Lu et al 2021b). However, flarerelated QPPs were rarely observed simultaneously in these channels.…”

Section: Introductionmentioning

confidence: 89%

Detection of flare multi-periodic pulsations in mid-ultraviolet Balmer continuum, Ly-alpha, hard X-ray, and radio emissions simultaneously

Li,

Ge,

Dominique

et al. 2021

Preprint

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Quasi-periodic pulsations (QPPs), which usually appear as temporal pulsations of the total flux, are frequently detected in the light curves of solar/stellar flares. In this study, we present the investigation of non-stationary QPPs with multiple periods during the impulsive phase of a powerful flare on 2017 September 06, which were simultaneously measured by the Large-Yield RAdiometer (LYRA) and the Hard X-ray Modulation Telescope (Insight-HXMT), as well as the ground-based BLENSW. The multiple periods, detected by applying a wavelet transform and Lomb-Scargle periodogram to the detrended light curves, are found to be ∼20−55 s in the Lyα and mid-ultraviolet Balmer continuum emissions during the flare impulsive phase. Similar QPPs with multiple periods are also found in the hard X-ray emission and low-frequency radio emission. Our observations suggest that the flare QPPs could be related to nonthermal electrons accelerated by the repeated energy release process, i.e., triggering of repetitive magnetic reconnection, while the multiple periods might be modulated by the sausage oscillation of hot plasma loops. For the multi-periodic pulsations, other generation mechanisms could not be completely ruled out.

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Ultraviolet, hard X-ray, and gamma-ray emission of solar flares recorded by VUSS-L and SONG instruments in 2001–2003

Cited by 17 publications

References 1 publication

Astrophysics in 2006

Astrophysics in 2006

The Lyman-alpha Emission in Solar Flares. I. a Statistical Study on Its Relationship with the 1--8 Å Soft X-ray Emission

Detection of flare multi-periodic pulsations in mid-ultraviolet Balmer continuum, Ly-alpha, hard X-ray, and radio emissions simultaneously

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