Multiwavelength Stereoscopic Observation of the 2013 May 1 Solar Flare and CME

Lastufka, Erica; Krucker, S.; Zimovets, I. V.; Nizamov, B. A.; White, S. M.; Masuda, S.; Golovin, D. I.; Litvak, M. L.; Митрофанов, И. Г.; Санин, А. Б.

doi:10.3847/1538-4357/ab4a0a

Cited by 7 publications

(2 citation statements)

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“…In summary, HXR observations show nonthermal emission at the footpoints of a flare loop, and the thermal emission comes from the flare loop itself (Benz 2017). In occulted flares, where the main flare footpoints are blocked by the solar limb, much fainter emission associated with the escaping CME is detected (Krucker et al 2007;Glesener et al 2013;Lastufka et al 2019). This indicates that nonthermal electrons during flares are not only injected toward the chromosphere and produce the flare ribbon HXR sources, but flare-accelerated electrons are also escaping into the core of the CME.…”

Section: Introductionmentioning

confidence: 93%

Solar flare hard X-rays from the anchor points of an eruptive filament

Stiefel

Battaglia

Barczynski

et al. 2023

A&A

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Context. We present an analysis of a GOES M1.8 flare with excellent observational coverage in UV, extreme-UV (EUV), and X-ray, including observations from the Interface Region Imaging Spectrograph (IRIS), from the Solar Dynamics Observatory (SDO) with the Atmospheric Imaging Assembly (AIA), from the Hinode/EUV Imaging Spectrometer (EIS), from the Hinode/X-ray Telescope (XRT), and from Solar Orbiter with the Spectrometer/Telescope for Imaging X-rays (STIX). Hard X-ray emission is often observed at the footpoints of flare loops and is occasionally observed in the corona. In this flare, four nonthermal hard X-ray sources are seen. Aims. Our aim is to understand why we can observe four individual nonthermal sources in this flare and how we can characterize the physical properties of these four sources. Methods. We used the multiwavelength approach to analyze the flare and characterize the four sources. To do this, we combined imaging at different wavelengths and spectroscopic fitting in the EUV and X-ray range. Results. The flare is eruptive with an associated coronal mass ejection, and it shows the classical flare picture of a heated flare loop seen in EUV and X-rays, and two nonthermal hard X-ray footpoints at the loop ends. In addition to the main flare sources, we observed two outer sources in the UV, EUV, and nonthermal X-ray range located away from the main flare loop to the east and west. The two outer sources are clearly correlated in time, and they are only seen during the first two minutes of the impulsive phase, which lasts a total of about four minutes. Conclusions. Based on the analysis, we determine that the outer sources are the anchor points of an erupting filament. The hard X-ray emission is interpreted as flare-accelerated electrons that are injected upward into the filament and then precipitate along the filament toward the chromosphere, producing Bremsstrahlung. While sources like this have been speculated to exist, this is the first report of their detection.

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Section: Introductionmentioning

confidence: 93%

Solar flare hard X-rays from the anchor points of an eruptive filament

Stiefel

Battaglia

Barczynski

et al. 2023

A&A

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“…Masuda et al (1994), Krucker et al (2008)). In cases of extreme occultation, so-called double coronal sources can even be observed well into the low-density regime high above the flare loop arcade (Chen et al (2017), Lastufka et al (2019)).…”

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GOES class estimation for behind-the-limb solar flares using MESSENGER SAX

Lastufka,

Krucker

2020

Preprint

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Mercury mission MESSENGER's Solar Assembly for X-rays (SAX) observed almost 700 solar flares between May 28, 2007 and August 19, 2013, as cataloged by Dennis et al. (2015. The SAX instrument, part of the X-ray Spectrometer (XRS), operated at 1 -10 keV, partially overlapping the energy range of the GOES X-ray spectrometers. SAX provides viewing angles different from the Earth-Sun line and can therefore be used as a GOES proxy for partially or fully occulted flares as seen from Earth. For flares with GOES classes above C2 seen on-disk for both instruments, we found an empirical relationship between the soft X-ray (SXR) fluxes measured by both SAX and GOES. Due to the different energy response of the two SXR instruments, individual events can deviate on average by about a factor of two from the empirical relationship, implying that predictions of the GOES class of occulted flares from SAX data are therefore accurate to within the same factor.The distinctive GOES energy response in combination with the multithermal nature of flares makes it difficult for any instrument, even other soft X-ray spectrometers, to provide a GOES proxy more accurate than a factor of two.

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