Hard X-ray and gamma-ray flares on the Sun: Stereoscopic effects near the limb from observations on the 2001 Mars Odyssey spacecraft and near-Earth spacecraft

Livshits, M. A.; Chernetskii, V. A.; Митрофанов, И. Г.; Kozyrev, A.; Litvak, M. L.; Санин, А. Б.; Tretyakov, V. I.; Boynton, W. V.; Shinohara, Kazunori; Hamara, D.

doi:10.1134/1.2127995

Cited by 5 publications

(4 citation statements)

References 8 publications

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“…Both scintillators are inside a light‐tight housing of ~2‐mm thickness (as seen from Figure 3 of Hurley et al, ), and both together have a sensitivity limit of ~2.5 MeV for high radiation fluxes. HEND records are somewhat more complex to evaluate than SEP because both scintillators are sensitive to neutrons, charged particles, and energetic photons (Livshits et al, ). As Livshits et al (, ) and Hurley et al () describe, the energy intervals that both scintillators can record are 60 keV–2 MeV for the inner detector and 30 keV–1 MeV for the outer detector.…”

Section: Observationsmentioning

confidence: 99%

“…HEND records are somewhat more complex to evaluate than SEP because both scintillators are sensitive to neutrons, charged particles, and energetic photons (Livshits et al, ). As Livshits et al (, ) and Hurley et al () describe, the energy intervals that both scintillators can record are 60 keV–2 MeV for the inner detector and 30 keV–1 MeV for the outer detector. The inner scintillator energy range includes radiation caused by the large number of electrons with energies ~100 keV, which produce gamma rays at the detector.…”

Section: Observationsmentioning

confidence: 99%

“…Previous studies of flare detections by HEND showed that the typical duration of a flare as recorded by this instrument is ~10–12 min, normally associated with photons with energy between 80 and 300 keV, having a sharp increase in counts, and are then followed by a slower decay. Moreover, a typical flare, if detected by HEND, does so independently of its position around the planet (see, e.g., Livshits et al, ; Livshits et al, ). We note that HEND's view of the Sun during this period was never obstructed by Mars, as the Sun was always in the FOV of Mars Odyssey throughout the Siding Spring encounter.…”

Section: Observationsmentioning

confidence: 99%

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Energetic Particle Showers Over Mars from Comet C/2013 A1 Siding Spring

et al. 2018

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This paper is a phenomenological description of multispacecraft observations of energetic particles caused by the close flyby of comet C/2013 A1 Siding Spring with Mars on 19 October 2014. This is the first time that cometary energetic particles have been observed at Mars. The Mars Atmosphere and Volatile EvolutioN (MAVEN)-solar energetic particle (SEP) and the Mars Odyssey-High Energy Neutron Detector (HEND) instruments recorded evidence of precipitating particles, which are likely O + pickup ions, during the~10 hr that Mars was within the region of the comet's coma. O + pickup ions were also detected several hours after, although whether their origin is the comet or space weather is not conclusive. We discuss the possible origin of those particles and also the cause of an additional shower of energetic particles that HEND observed between 22 and 35 hr after the comet's closest approach, which may be related to dust impacts from the comet's dust tail. An O + pickup ion energy flux simulation is performed with representative solar wind and cometary conditions, together with a simulation of their energy deposition profile in the atmosphere of Mars. Results indicate that the O + pickup ion fluxes observed by SEP were deposited in the ionosphere around 105 to 120 km altitude, and they are compared with precomet flyby estimations of cometary pickup ions. The comet's flyby deposited a significant fluence of energetic particles into Mars' upper atmosphere, at a similar level to a large space weather event.

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Section: Observationsmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

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Energetic Particle Showers Over Mars from Comet C/2013 A1 Siding Spring

et al. 2018

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“…HEND facility has been working stably since 2001, and there have been registered about 100 flares during 16 years. Some results have already been published in [4][5][6][7]. The most interesting appeared to be a study of the phenomena observed on the solar disk from the near-Mars and near-Earth orbits (with RHESSI).…”

Section: Introductionmentioning

confidence: 99%

Catalog of hard X-ray solar flares detected with Mars Odyssey/HEND from the Mars orbit in 2001–2016

et al. 2017

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The study of nonstationary processes in the Sun is of great interest, and lately, multiwavelength observations and registration of magnetic fields are carried out by means of both ground-based telescopes and several specialized spacecraft (SC) on near-Earth orbits. However the acquisition of the new reliable information on their hard X-ray radiation remains demanded, in particular if the corresponding SC provide additional information, e.g. in regard to the flare observations from the directions other than the Sun-Earth direction. In this article we present a catalog of powerful solar flares registered by the High Energy Neutron Detector (HEND) device designed in the Space Research Institute (IKI) of Russian Academy of Sciences. HEND is mounted onboard the 2001 Mars Odyssey spacecraft. It worked successfully during the flight to Mars and currently operates in the near-Mars orbit. Besides neutrons, the HEND instrument is sensitive to the hard X-ray and gamma radiation. This radiation is registered by two scintillators: the outer one is sensitive to the photons above 40 keV and the inner one to the photons above 200 keV. The catalog was created with the new procedure of the data calibration. For most powerful 60 solar flares on the visible and on the far sides of the Sun (in respect to a terrestrial observer), we provide time profiles of flare radiation, summed over all the channels of X-ray and in some cases of gamma-ray bands as well as the spectra and characteristics of their power law approximation. We briefly discuss the results of the previous articles on the study of the Sun with HEND instrument and the potential of the further use of these data.

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