Gamma Rays Generated in Nuclear Interactions of Protons Accelerated during Solar Flares

2020 ◽  
Vol 60 (7) ◽  
pp. 958-965
Author(s):  
G. I. Vasil’ev ◽  
E. A. Bogomolov
Keyword(s):  
Gamma Rays ◽  
Solar Flares ◽  
Nuclear Interactions

Production of neutrons and gamma rays by nuclear interactions in solar flares

1968 ◽  
Vol 46 (10) ◽  
pp. S780-S783 ◽  
Author(s):  
K. Ito ◽  
H. Okazoe ◽  
M. Yoshimori
Keyword(s):  
Solar Atmosphere ◽  
Gamma Rays ◽  
Solar Flares ◽  
Directed Motion ◽  
Solar Neutron ◽  
Neutron Intensity ◽  
Nuclear Interactions ◽  
Solar Material ◽  
Accelerated Particles

In recent years, the possibility has been discussed by various authors that solar neutrons and 2.2-MeV gamma rays are produced by the nuclear interactions of flare-accelerated particles with solar material. In this paper, it is emphasized that the ratio of neutrons to 2.2-MeV gamma rays depends significantly on the direction of motion of the flare-accelerated particles with respect to the solar atmosphere. For the direction of motion of flare-accelerated particles, we shall consider three cases: (a) isotropic motion, (b) upward-directed motion towards the corona, (c) downward-directed motion towards the photosphere. These flare-accelerated particles would interact with the solar atmosphere to produce neutrons with energies above several MeV. Some of the neutrons will escape into space through the corona, while some will be slowed down in the denser atmosphere and captured by the atmospheric protons with the emission of 2.2-MeV gamma rays.According to the calculations in this paper, the ratio of neutrons to 2.2-MeV gamma rays for case (b) is 10–20 times that for (a) or (c). The value for case (c) is twice that for case (a). For the expected solar neutron intensity, the values for (b) and (c) are ~10−6 and 4 × 10−2 of that for (a), respectively.

scholarly journals Gamma-rays from Solar Flares

2000 ◽  
Vol 195 ◽  
pp. 123-132 ◽  
Author(s):  
R. Ramaty ◽  
N. Mandzhavidze
Keyword(s):  
Energy Release ◽  
Gamma Rays ◽  
Solar Flares ◽  
Gamma Ray ◽  
Particle Interaction ◽  
Mass Motion ◽  
Relativistic Electrons ◽  
Total Energy Release ◽  
Flare Energy ◽  
Accelerated Particles

Gamma-ray emission is the most direct diagnostic of energetic ions and relativistic electrons in solar flares. Analysis of solar flare gamma-ray data has shown: (i) ion acceleration is a major consequence of flare energy release, as the total flare energy in accelerated particles appears to be equipartitioned between ≳ 1 MeV/nucleon ions and ≳ 20 keV electrons, and amounts to an important fraction of the total energy release; (ii) there are flares for which over 50% of the energy is in a particles and heavier ions; (iii) in both impulsive and gradual flares, the particles that interact at the Sun and produce gamma rays are essentially always accelerated by the same mechanism that operates in impulsive flares, probably stochastic acceleration through gyroresonant wave particle interaction; and (iv) gamma-ray spectroscopy can provide new information on solar abundances, for example the site of the FIP-bias onset and the photospheric 3He abundance. We propose a new technique for the investigation of mass motion and mixing in the solar atmosphere: the observations of gamma-ray lines from long-term radioactivity produced by flare accelerated particles.

scholarly journals Millimeter and Microwave Activity of the Sun

1990 ◽  
Vol 142 ◽  
pp. 457-465 ◽  
Author(s):  
M. R. Kundu ◽  
S. M. White
Keyword(s):  
Magnetic Field ◽  
Gamma Rays ◽  
Solar Flares ◽  
Gamma Ray ◽  
High Spatial Resolution ◽  
High Resolution Imaging ◽  
The Sun ◽  
Millimeter Wavelengths ◽  
Resolution Imaging ◽  
The Magnetic Field

The emission of solar flares at millimeter wavelengths is of great interest both in its own right and because it is generated by the energetic electrons which also emit gamma rays. Since high-resolution imaging at gamma-ray energies is not presently possible, millimeter observations can act as a substitute. Except for that class of flares known as gamma-ray flares the millimetric emission is optically thin. It can be used as a powerful diagnostic of the energy distribution of electrons in solar flares and its evolution, and of the magnetic field. We have carried out high-spatial-resolution millimeter observations of solar flares this year using the Berkeley-Illinois-Maryland Array (BIMA), and report on the preliminary results in this paper (Kundu et al 1990; White et al 1990). We also report some recent results obtained from multifrequency observations using the VLA (White et al 1990).

scholarly journals Preface

1991 ◽  
Vol 336 (1643) ◽  
pp. 323-323
Keyword(s):  
Solar Flare ◽  
Energy Release ◽  
Gamma Rays ◽  
Solar Flares ◽  
Solar Maximum ◽  
Interplanetary Space ◽  
Release Site ◽  
Solar Maximum Mission ◽  
New Information ◽  
Three Space

During the period of the 1980 solar maximum three space missions (P78-1, Solar Maximum Mission and Hinotori ) carried out extensive studies of solar flares. In their different ways all of these missions contributed significant new information to our understanding of the solar flare phenomenon. In this volume the contribution made by these three spacecraft to the study of the energy release and the related creation of high-tem perature plasma, the transport of energy from the primary release site, the production of gamma-rays at energies up to 10 MeV and the ejection of solar matter into interplanetary space are reviewed.

Gamma rays from pion decay - Evidence for long-term trapping of particles in solar flares

1992 ◽  
Vol 396 ◽  
pp. L111 ◽  
Author(s):  
Natalie Mandzhavidze ◽  
Reuven Ramaty
Keyword(s):  
Gamma Rays ◽  
Solar Flares ◽  
Pion Decay

High-Energy Solar Gamma-Ray Observations

1998 ◽  
Vol 11 (2) ◽  
pp. 755-758
Author(s):  
M. Yoshimori ◽  
N. Saita ◽  
A. Shiozawa
Keyword(s):  
Particle Acceleration ◽  
Gamma Rays ◽  
Solar Flares ◽  
Gamma Ray ◽  
Solar Maximum ◽  
High Energy ◽  
The Sun ◽  
Long Duration ◽  
New Findings ◽  
Gamma Ray Emission

In the last solar maximum, gamma-rays associated with solar flares were observed with GRANAT, GAMMA-1, CGRO and YOHKOH. The gamma-ray energies ranged from 100 keV to a few GeV. We obtained several new findings of gamma-ray emission on the Sun: (1) Gamma-ray production in the corona, (2) GeV gamma-ray production in very long duration flares, (3) Electron-rich flares, (4) Gamma-ray lines and solar atmospheric abundances and (5) Possible location of gamma-ray emission. We present the observations of these new findings and discuss high energy phenomena relating to particle acceleration and gamma-ray production during solar flares.

scholarly journals Gamma-Ray Precursors of Solar Flares

1994 ◽  
Vol 142 ◽  
pp. 645-648
Author(s):  
E. Rieger
Keyword(s):  
Spatial Resolution ◽  
Gamma Rays ◽  
Solar Flares ◽  
Gamma Ray ◽  
High Energy ◽  
X Rays ◽  
High Energy Gamma ◽  
Gamma Ray Spectrometer ◽  
Energy Gamma ◽  
Negligible Contribution

AbstractBursts have been observed by the gamma-ray spectrometer on SMM at medium- and high-energy gamma-rays that precede the flare maximum. The negligible contribution of nuclear lines in the spectra of these events and their impulsive appearance suggests that they are hard-electron-dominated events superposed on the flares. Spatial resolution at gamma-ray energies will be necessary to decide whether this kind of bursts is cospatial with the flares or whether they occur in the flares’ vicinity.Subject headings: Sun: flares — Sun: X-rays, gamma rays

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