Neutron and gamma-ray measurements of the solar flare of 1991 June 9

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

doi:10.1063/1.45205

Cited by 11 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Having the ability to determine the direction of the incoming neutron would significantly reduce the possibility that secondary neutrons could be mistakenly attributed to neutrons originating at the Sun. This capability would also vastly improve the detector's sensitivity for detecting solar neutrons, as has been demonstrated with the COMPTEL instrument on the Compton Gamma Ray Observatory [ Ryan et al , ]. Early designs for such neutron detectors at energies above 30 MeV, which also provide information on the energy of the neutrons, have been discussed in a review by Frye et al [].…”

Section: Discussionmentioning

confidence: 99%

“…Since that time other detections of >10 MeV solar neutrons were made by spectrometers in low‐Earth orbit [e.g., Ryan et al , ; Murphy et al , ; Kuznetsov et al , ]. Most of these measurements were made with omnidirectional detectors which relied on differences in pulse‐shape discrimination or in energy deposition to distinguish the solar neutrons from flare‐produced high‐energy gamma rays.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Misidentification of the source of a neutron transient detected by MESSENGER on 4 June 2011

Murphy

Tylka

et al. 2015

JGR Space Physics

View full text Add to dashboard Cite

Low‐energy (1–10 MeV) neutrons emanating from the Sun provide unique information about accelerated ions with steep energy spectra that may be produced in weak solar flares. However, observation of these solar neutrons can only be made in the inner heliosphere where measurement is difficult due to high background rates from neutrons produced by energetic ions interacting in the spacecraft. These ions can be from solar energetic particle events or produced in passing shocks associated with fast coronal mass ejections. Therefore, it is of the utmost importance that investigators rule out these secondary neutrons before making claims about detecting neutrons from the Sun. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) neutron spectrometer recorded an hour‐long neutron transient beginning at 15:45 UTC on 4 June 2011 for which Lawrence et al. (2014) claim there is “strong evidence” that the neutrons were produced by the interaction of ions in the solar atmosphere. We studied this event in detail using data from the MESSENGER neutron spectrometer, gamma ray spectrometer, X‐ray Spectrometer, and Energetic Particle Spectrometer and from the particle spectrometers on STEREO A. We demonstrate that the transient neutrons were secondaries produced by energetic ions, probably accelerated by a passing shock, that interacted in the spacecraft. We also identify significant faults with the authors' arguments in favor of a solar neutron origin for the transient.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Misidentification of the source of a neutron transient detected by MESSENGER on 4 June 2011

Murphy

Tylka

et al. 2015

JGR Space Physics

View full text Add to dashboard Cite

show abstract

“…Some of the most recent events have been observed in a wide energy range by both RHESSI and CORONAS-F (e.g., Kuznetsov et al 2008;Trottet et al 2008;Masson et al 2009) (see, e.g., Figure 3.1). For some of the events, high-energy emission has been observed for hours after the impulsive phase of the flare, revealing that high energy ions must be continuously accelerated on long timescales in some flares (e.g., Kanbach et al 1993;Ryan et al 1994;Ryan 2000;Rank et al 2001). Quantitative analysis of a few of the events with significant pion production has been performed providing information on the ion energy spectrum at energies greater than 300 MeV and allowing a comparison of this spectrum with the one deduced at lower energies from γ-ray line spectroscopy (see e.g., Alexander et al 1994;Kocharov et al 1994Kocharov et al , 1998.…”

Section: Pion-decay Radiation In Solar Flaresmentioning

confidence: 99%

Properties of Energetic Ions in the Solar Atmosphere from γ-Ray and Neutron Observations

Vilmer¹,

MacKinnon²,

Hurford³

2011

High-Energy Aspects of Solar Flares

View full text Add to dashboard Cite

Gamma-rays and neutrons are the only sources of information on energetic ions present during solar flares and on properties of these ions when they interact in the solar atmosphere. The production of γ-rays and neutrons results from convolution of the nuclear cross-sections with the ion distribution functions in the atmosphere. The observed γ-ray and neutron fluxes thus provide useful diagnostics for the properties of energetic ions, yielding strong constraints on acceleration mechanisms as well as properties of the interaction sites. The problem of ion transport between the accelerating and interaction sites must also be addressed to infer as much information as possible on the properties of the primary ion accelerator. In the last couple of decades, both theoretical and observational developments have led to substantial progress in understanding the origin of solar γ-rays and neutrons. This chapter reviews recent developments in the study of solar γ-rays and of solar neutrons at the time of the RHESSI era. The unprecedented quality of the RHESSI data reveals γray line shapes for the first time and provides γ-ray images. Our previous understanding of the properties of energetic ions based on measurements from the former solar cycles is also summarized. The new results -obtained owing both to the gain in spectral resolution (both with RHESSI and with the non solar-dedicated INTEGRAL/SPI instrument) and to the pioneering imaging technique in the γ-ray domain -are presented in the context of this previous knowledge. Still open questions are emphasized in the last section of the chapter and future perspectives on this field are briefly discussed.

show abstract

“…Among them, flares of June 4th, 6th, 9th and 11th of 1991 occurred at Japanese local noon and a wealth of valuable scientific data was obtained by Japanese instruments located at ground level (Sakurai et a!., 1992;Enome and Nakajima, 1991) as well as by the instruments on board the CGRO satellite (Schwartz et al, 1992;Ryan et a!., 1993;Murphy et al, 1993). Here we report on these novel phenomena.…”

Section: Introductionmentioning

confidence: 98%

New Solar Neutron Detector and Large Solar Flare Events of June 4th and 6th, 1991.

Muraki

Sakakibara

Shibata

et al. 1995

J. geomagn. geoelec

View full text Add to dashboard Cite

Neutron and gamma-ray measurements of the solar flare of 1991 June 9

Cited by 11 publications

References 0 publications

Misidentification of the source of a neutron transient detected by MESSENGER on 4 June 2011

Misidentification of the source of a neutron transient detected by MESSENGER on 4 June 2011

Properties of Energetic Ions in the Solar Atmosphere from γ-Ray and Neutron Observations

New Solar Neutron Detector and Large Solar Flare Events of June 4th and 6th, 1991.

Contact Info

Product

Resources

About