scholarly journals Variations of the relative abundances of He, (C, N, O) and Fe-group nuclei in solar cosmic rays and their relationship to solar particle acceleration

Solar Physics ◽  
1973 ◽  
Vol 31 (1) ◽  
Author(s):  
D.L. Bertsch ◽  
S. Biswas ◽  
C.E. Fichtel ◽  
C.J. Pellerin ◽  
D.V. Reames
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Solar Cosmic Rays ◽  
Solar Particle ◽  
Relative Abundances

A Discussion on solar studies with special reference to space observations - Solar cosmic rays

1971 ◽  
Vol 270 (1202) ◽  
pp. 167-174 ◽  
Keyword(s):  
Cosmic Rays ◽  
Special Reference ◽  
Source Region ◽  
Mass Ratio ◽  
Solar Cosmic Rays ◽  
Charge Mass ◽  
Relative Abundances ◽  
Solar Particles ◽  
Precise Interpretation ◽  
Space Observations

A wealth of data on many aspects of solar cosmic rays has been collected over the last decade. One of the most striking features of these events has been the tremendous variation in many of their characteristics and the related difficulty of precise interpretation. However, one feature of the solar cosmic rays which does seem to be constant from event to event and within an event is the relative abundances of the multicharged nuclei with the same charge: mass ratio. This paper will concentrate on observations of the composition of solar particles and their interpretation. A brief discussion on the propagation of the energetic solar particles including a few comments on the source region will also be given.

scholarly journals Solar cosmic rays during the extremely high ground level enhancement on 23 February 1956

2005 ◽  
Vol 23 (6) ◽  
pp. 2281-2291 ◽  
Author(s):  
A. Belov ◽  
E. Eroshenko ◽  
H. Mavromichalaki ◽  
C. Plainaki ◽  
V. Yanke
Keyword(s):  
Cosmic Rays ◽  
Particle Density ◽  
Cosmic Ray ◽  
Ground Level ◽  
Particle Energy ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
Solar Particle ◽  
Small Width ◽  
Standard Design

Abstract. The 23 February 1956 ground level enhancement of the solar cosmic ray intensity (GLE05) is the most famous among the proton events observed since 1942. But we do not have a great deal of information on this event due to the absence of solar wind and interplanetary magnetic field measurements at that time. Furthermore, there were no X-Ray or gamma observations and the information on the associated flare is limited. Cosmic ray data was obtained exclusively by ground level detectors of small size and in some cases of a non-standard design. In the present work all available data from neutron monitors operating in 1956 were analyzed, in order to develop a model of the solar cosmic ray behavior during the event. The time-dependent characteristics of the cosmic ray energy spectrum, cosmic ray anisotropy, and differential and integral fluxes have been evaluated utilizing different isotropic and anisotropic models. It is shown that the most outstanding features of this proton enhancement were a narrow and extremely intense beam of ultra-relativistic particles arriving at Earth just after the onset and the unusually high maximum solar particle energy. However, the contribution of this beam to the overall solar particle density and fluency was not significant because of its very short duration and small width. Our estimate of the integral flux for particles with energies over 100 MeV places this event above all subsequent. Perhaps the number of accelerated low energy particles was closer to a record value, but these particles passed mainly to the west of Earth. Many features of this GLE are apparently explained by the peculiarity of the particle interplanetary propagation from a remote (near the limb) source. The quality of the available neutron monitor data does not allow us to be certain of some details; these may be cleared up by the incorporation into the analysis of data from muonic telescopes and ionization chambers operating at that time. Keywords. Interplanatary physics (Cosmic rays; Energetic particles) – Solar physics, astrophysics and astronomy (Flares and mass injections)

scholarly journals Transport of Solar Energetic Particles

1994 ◽  
Vol 142 ◽  
pp. 567-576
Author(s):  
Wolfgang Dröge
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cosmic Rays ◽  
Linear Theory ◽  
Interplanetary Medium ◽  
Galactic Cosmic Rays ◽  
Transport Parameters ◽  
Solar Cosmic Rays ◽  
Solar Particle Events ◽  
Solar Particle

AbstractNew developments in the understanding of the interplanetary transport of solar cosmic rays are reviewed. Based on carefully analyzed solar particle events observed on the Helios and ISEE 3 spacecraft, the relation of transport parameters to the structure of the interplanetary magnetic field is discussed. Special emphasis is given to a comparison of particle mean free paths determined from fits to intensity and anisotropy profiles with theoretical predictions derived from magnetic field spectra measured at the time of the solar particle event. Different aspects of the turbulence and wave models for the magnetic fluctuations are considered, including the effects resulting from the finite temperature of the plasma and of resonance broadening. It is found that a modified quasi-linear theory of particle scattering taking into account the effects of plasma waves propagating with respect to the average solar wind flow and the proper treatment of the dispersion relation at high wavenumber gives results which are in several cases in good agreement with particle observations in the interplanetary medium between 0.3 and 1 AU, indicating that quasi-linear theory is probably a good approximation to a full theory of solar particle transport. This has important implications for other astrophysical problems where quasi-linear theory is often used, such as the propagation and acceleration of Galactic cosmic rays and particle acceleration at shock waves.Subject headings: acceleration of particles — cosmic rays — interplanetary medium — MHD — solar wind — Sun: particle emission

scholarly journals On particle acceleration and transport in plasmas in the Galaxy: theory and observations

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Elena Amato ◽  
Sabrina Casanova
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Quality Data ◽  
Current Status ◽  
The Earth ◽  
The Galaxy ◽  
Formation And Evolution ◽  
Galaxy Assembly

Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU scale relevant for the formation and evolution of stars and planets to the Mpc scale involved in Galaxy assembly. We reveal the presence of energetic particles in many classes of astrophysical sources thanks to their production of non-thermal radiation, and we detect them directly at the Earth as cosmic rays. In the last two decades both direct and indirect observations have provided us a wealth of new, high-quality data about cosmic rays and their interactions both in sources and during propagation, in the Galaxy and in the Solar System. Some of the new data have confirmed existing theories about particle acceleration and propagation and their interplay with the environment in which they occur. Some others have brought about interesting surprises, whose interpretation is not straightforward within the standard framework and may require a change of paradigm in terms of our ideas about the origin of cosmic rays of different species or in different energy ranges. In this article, we focus on cosmic rays of galactic origin, namely with energies below a few petaelectronvolts, where a steepening is observed in the spectrum of energetic particles detected at the Earth. We review the recent observational findings and the current status of the theory about the origin and propagation of galactic cosmic rays.

scholarly journals The Chemical Composition of Cometary Nuclei

1972 ◽  
Vol 45 ◽  
pp. 265-270
Author(s):  
L. M. Shul'man
Keyword(s):  
Chemical Composition ◽  
Cosmic Rays ◽  
Organic Molecules ◽  
Solid Phase ◽  
Critical Concentration ◽  
Energy Output ◽  
Time Interval ◽  
Nuclear Surface ◽  
Solar Cosmic Rays ◽  
Cometary Nuclei

The probable parent-molecules of radicals such as C3 and N2+ are discussed, and it is concluded that cometary nuclei may contain complicated organic molecules, such as C3H4, CH2N2, and C4H2. It is suggested that these molecules are formed by radiation synthesis in solid phase. In a time interval of order 107 to 109 yr bombardment from cosmic rays would be expected to transform the chemical composition to a depth of 1 m. Solar cosmic rays do not penetrate as far, and as a result the surface layer of the nucleus can be enriched with unsaturated hydrocarbons. After a critical concentration of this explosive material is reached a further burst of solar cosmic rays can initiate an explosion and thus an outburst in the comet's brightness. This mechanism is the only one advanced to date that can explain the synchronism of the energy output over the whole nuclear surface.

The influence of nonthermal particles and radiation on the charge state of heavy ions in solar cosmic rays

2004 ◽  
Vol 48 (9) ◽  
pp. 759-768
Author(s):  
Yu. Yu. Kartavykh ◽  
V. M. Ostryakov ◽  
E. Möbius ◽  
M. A. Popecki
Keyword(s):  
Cosmic Rays ◽  
Charge State ◽  
Heavy Ions ◽  
Solar Cosmic Rays ◽  
Nonthermal Particles

scholarly journals Propagation of an MHD Shock in the Vicinity of a Magnetic Neutral Sheet

1980 ◽  
Vol 91 ◽  
pp. 323-326
Author(s):  
D. J. Mullan ◽  
R. S. Steinolfson
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Solar Corona ◽  
Large Scale ◽  
Field Structure ◽  
Neutral Sheet ◽  
Solar Cosmic Rays ◽  
Magnetic Field Structure ◽  
Large Scale Magnetic Field ◽  
Highly Correlated

The acceleration of solar cosmic rays in association with certain solar flares is known to be highly correlated with the propagation of an MHD shock through the solar corona (Svestka, 1976). The spatial structure of the sources of solar cosmic rays will be determined by those regions of the corona which are accessible to the flare-induced shock. The regions to which the flare shock is permitted to propagate are determined by the large scale magnetic field structure in the corona. McIntosh (1972, 1979) has demonstrated that quiescent filaments form a single continuous feature (a “baseball stitch”) around the surface of the sun. It is known that helmet streamers overlie quiescent filaments (Pneuman, 1975), and these helmet streamers contain large magnetic neutral sheets which are oriented essentially radially. Hence the magnetic field structure in the low solar corona is characterized by a large-scale radial neutral sheet which weaves around the entire sun following the “baseball stitch”. There is therefore a high probability that as a shock propagates away from a flare, it will eventually encounter this large neutral sheet.

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