COMPTEL gamma ray and neutron measurements of solar flares

Ryan, J.; Forrest, D. J.; Lockwood, J. A.; Loomis, M.; McConnell, M.; Morris, David J.; Webber, W. R.; Rank, G.; Schönfelder, V.; Swanenburg, B. N.; Bennett, K.; Hanlon, L.; Winkler, C.; Debrunner, H.

doi:10.1063/1.44245

Cited by 5 publications

(5 citation statements)

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“…In almost mutually exclusive observations, GAMMA-1 measured g-ray emissions up to 1 GeV ) after which COMPTEL measured the g-ray flux <30 MeV until 09:45 UT (McConnell et al 1993;Ryan et al 1993b). Both spacecraft were occulted during the impulsive phase.…”

Section: The Event Of 15 June 1991mentioning

confidence: 99%

Solar Neutrons and Related Phenomena

Дорман¹

2010

Astrophysics and Space Science Library

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Section: The Event Of 15 June 1991mentioning

confidence: 99%

Solar Neutrons and Related Phenomena

Дорман¹

2010

Astrophysics and Space Science Library

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“…The 11 June flare emitted gamma rays for a period of over 8 hours. The flare of 1991 June 9 (Ryan et al, 1993) was of much lower intensity than the others but by virtue of the sensitivity of the instruments on CGRO, the measurements reveal that it too was a long-duration, high-energy event. This phenomenon of pion-related high-energy gamma-ray emission was observed earlier on SMM , but the new measurements push theoretical models to the limit.…”

Section: Long-duration High-energy Flaresmentioning

confidence: 79%

“…Being able to measure the energy of individual neutrons means that neutron emission can be studied in the same manner as gamma-ray emission, i.e., measuring the neutron spectrum at the time of emission. The neutron emission from the 1991 June 9 event (Ryan et al 1993) primarily occurs after the impulsive phase. This clearly identifies the long-duration emission as having a proton rather than an electron origin.…”

Section: Neutron Measurementsmentioning

confidence: 99%

Commission 10: Solar Activity (Activité Solaire)

1994

Trans. Int. Astron. Union

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The Sun's activity may have declined in the three years since the last report, but the solar community carries on its research at a vigorous pace. During that interval there have been six IAU Symposia/Colloquia sponsored (or co-sponsored) by this commission on topics related to solar activity. Numerous activity-related conferences and workshops supported by other bodies attest to the vibrant interest in, and committement to, research on the wide range of topics which encompass this discipline. Flare research continues as the dominant topic, and is now fueled by a new generation of ground-based instruments and a highly successful solar satellite-Yohkoh (formerly Solar-A). Other recent space missions, although not devoted entirely to solar flares, are likely to have a profound bearing on our understanding of flare issues. They include, among others, the continuing series of sounding rocket flights of the Normal Incidence X-ray Telescope (NIXT), the Compton Gamma Ray Observatory (CGRO), designed to observe energetic phenomena in the Universe, and GRANAT, which is also dedicated to high-energy astronomy. The flare problem spurs research into many related subjects: active-region formation, physical proceses in prominences and filaments, coronal mass ejections, even periodicities in solar activity. This last topic is given separate attention here in order to draw attention to the still obscure link between the Sun's interior and the activity at its surface. It is a pleasure to thank the individual reviewers who took time from their busy schedules to write separate sections of this report. As well as moments of triumph, there have been moments of anxiety, disappointment, and sadness for the solar community. Substantial numbers of solar astronomers and solar physicists in the states of the former Soviet Union live under stressful circumstances as struggles go on to form new political systems in their homelands. Elsewhere ambitious plans for new ground-based or space facilities have been delayed as a worldwide recession continues. And the community has been saddened by the loss of pioneering figures who had a major impact on shaping our discipline: Prof. Keizo Kai, former chief of the solar radio group at the Nobeyama Radio Observatory, Prof. Zenzaburo Suemoto, former director of the Tokyo Astronomical Observatory, Prof. Giuseppe Vaiana, best known in his role as principal investigator of the S054 experiment on Skylab, Dr. Mstislav N. Gnevyshev, founder and director of the Kislovodsk Solar Station of the Central Astronomical Observatory of the Russian Academy of Sciences. They will remain alive in our memory and in our work, which builds upon their considerable achievements. New devices under construction include a continuous face-plate mirror with 218 mm clear aperture and 61 actuators (Dunn et al. 1991), and a coronagraph with adaptive optics using a membrane mirror with 91 actuators (Clampin et al. 1991).

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“…In fact, observations of persistent 2.2 MeV c-ray emission suggest that there may be significant fluxes of trapped and/or continually accelerated nuclei at the Sun following a solar flare (e.g., Rank et al, 2001). To date, solar neutrons above about 20 MeV have been directly detected for a few events by instruments on the SMM (e.g., Chupp et al, 1987) and CGRO spacecraft (Ryan et al, 1993), and, at higher energies, by neutron monitors (Chupp et al, 1987;Shea et al, 1991). Given the often intense competing backgrounds and limited survival of MeV neutrons to reach the orbit of Earth, relevant data on neutrons produced in association with solar energetic particle (SEP) events are generally sparse and fragmentary.…”

Section: Introductionmentioning

confidence: 99%