Cosmic-ray propagation in the Galaxy and in the heliosphere - The path-length distribution at low energy

1987 ◽  
Vol 64 ◽  
pp. 269 ◽  
Author(s):  
M. Garcia-Munoz ◽  
J. A. Simpson ◽  
T. G. Guzik ◽  
J. P. Wefel ◽  
S. H. Margolis
Keyword(s):  
Path Length ◽  
Length Distribution ◽  
Cosmic Ray ◽  
Low Energy ◽  
The Galaxy

scholarly journals Interpretation of cosmic ray composition - The path length distribution

1981 ◽  
Vol 247 ◽  
pp. 362 ◽  
Author(s):  
R. J. Protheroe ◽  
J. F. Ormes ◽  
G. M. Comstock
Keyword(s):  
Path Length ◽  
Length Distribution ◽  
Cosmic Ray

Cosmic-ray deuterium and helium-3 nuclei

1968 ◽  
Vol 46 (10) ◽  
pp. S627-S632 ◽  
Author(s):  
R. Ramaty ◽  
R. E. Lingenfelter
Keyword(s):  
Cross Sections ◽  
Solar Minimum ◽  
Path Length ◽  
Cosmic Ray ◽  
Unique Determination ◽  
The Earth ◽  
The Galaxy ◽  
Helium 3 ◽  
Field Modulation ◽  
Ray Path

Assuming that cosmic-ray deuterons and helium-3 nuclei are of secondary origin, we show that a unique determination of both the cosmic-ray path-length and the residual interplanetary field modulation at solar minimum may be made from a comparison of the calculated and measured intensities of these two nuclei. This determination does not depend on any assumptions regarding either the source spectra or the unmodulated proton to alpha particle ratio of the primary cosmic rays. The production of deuterium and helium-3 by cosmic-ray interactions in the galaxy is calculated considering energy-dependent cross sections, interaction kinematics, and demodulated cosmic-ray spectra. The resulting flux at the earth is obtained by taking into account leakage from the galaxy, ionization losses, nuclear breakup, and modulation. From a comparison of these calculations with the measured deuterium and helium-3 intensities at the earth, we conclude that within the experimental uncertainties all the data can be understood in terms of an energy-independent cosmic-ray path-length of 4 ± 1 g/cm2 and a residual interplanetary field modulation at solar minimum of the form exp(–η/Pβ) with η = 0.4 ± 0.1 BV, where P and β are the rigidity and velocity.

scholarly journals The composition of galactic cosmic rays

1968 ◽  
Vol 46 (10) ◽  
pp. S544-S547 ◽  
Author(s):  
D. V. Reames ◽  
C. E. Fichtel
Keyword(s):  
Cosmic Rays ◽  
Cross Sections ◽  
Length Distribution ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Interstellar Space ◽  
Fermi Acceleration ◽  
Fixed Amount ◽  
The Galaxy

Recent measurements of low-energy galactic cosmic rays obtained on sounding rockets and satellites exhibit a composition different from that obtained for intermediate and high-energy radiation obtained at balloon altitudes. In particular the ratio of light to medium nuclei is observed to be 0.2–0.3 in the 50–100 MeV/nucleon interval as compared with values near 0.5 in the 200–500 MeV/nucleon region. Lower values of the ratios C/O, N/O, F/O, and odd-Z/even-Z are also found. In the light of these new measurements and of new measurements on the fragmentation cross sections for cosmic-ray nuclei in interstellar space, an attempt has been made to calculate the composition expected if similar source spectra are assumed. It is found that neither passage through a fixed amount of material nor an equilibrium condition (exponential path-length distribution) is adequate to explain the observed features. The effects of including other mechanisms such as rigidity-dependent escape from the galaxy and Fermi acceleration in interstellar space are evaluated.

scholarly journals Low-energy cosmic ray positrons and 0.51-Mev gamma rays from the galaxy

1970 ◽  
Vol 75 (7) ◽  
pp. 1141-1149 ◽  
Author(s):  
R. Ramaty ◽  
F. W. Stecker ◽  
D. Misra
Keyword(s):  
Gamma Rays ◽  
Cosmic Ray ◽  
Low Energy ◽  
The Galaxy

scholarly journals The Origin and Dynamical Effects of the Magnetic Fields and Cosmic Rays in the Disk of the Galaxy

1970 ◽  
Vol 39 ◽  
pp. 168-183
Author(s):  
E. N. Parker
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Dynamical Behavior ◽  
Cosmic Ray ◽  
Interested Reader ◽  
Written Text ◽  
The Galaxy ◽  
Basic Ideas ◽  
The Magnetic Field

The topic of this presentation is the origin and dynamical behavior of the magnetic field and cosmic-ray gas in the disk of the Galaxy. In the space available I can do no more than mention the ideas that have been developed, with but little explanation and discussion. To make up for this inadequacy I have tried to give a complete list of references in the written text, so that the interested reader can pursue the points in depth (in particular see the review articles Parker, 1968a, 1969a, 1970). My purpose here is twofold, to outline for you the calculations and ideas that have developed thus far, and to indicate the uncertainties that remain. The basic ideas are sound, I think, but, when we come to the details, there are so many theoretical alternatives that need yet to be explored and so much that is not yet made clear by observations.

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