Gravitation, Cosmology, and Cosmic-Ray Physics (1986) / Chapter Skim
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15. Overview
15. Overview
Pages 115-120
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From page 115... ...
In fact, recent observations suggest that cosmic rays may actually represent a more typical sample of the average interstellar medium than the solar-system material, which may have been contaminated by a nearby supernova explosion. The differences between cosmic rays and solar-system material are both significant and subtle.
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From page 116... ...
Particle acceleration is evidently a common occurrence in a wide variety of astrophysical settings. The total energy required to keep the galaxy filled with cosmic rays is enormous; it requires a substantial fraction of the energy released by massive stars such as supernova exploding at the rate of one every 30 years somewhere in the galaxy.
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From page 117... ...
The cosmic rays themselves also affect conditions in their confinement volume by ionizing material in molecular clouds, ''blowing out" magnetic field lines, and generating secondary particles and photons through several different nuclear and electromagnetic processes. Major components of the diffuse radio and gamma-ray backgrounds are produced by cosmic rays.
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From page 118... ...
The solid curve shows the hydrogen spectrum extrapolated to interstellar space by unfolding the effects of solar modulation. The turn-up of the helium flux below ~60 MeV n-' is due to the additional flux of the anomalous 4He component.
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From page 119... ...
Because the flux of the primary cosmic rays is so low at these energies, the relatively small detectors in spacecraft or balloons cannot intercept a large enough number for study. Large detectors can be
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From page 120... ...
Because the interpretation of cosmic-ray cascades in terms of particle physics depends on the identity of the initiating cosmic ray (e.g., proton, carbon, or iron nucleus) and vice versa, our understanding of both areas is interrelated, and progress is made in an iterative, bootstrap manner as we move to higher energies.
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