Origin of Galactic Cosmic Rays

we cannot yet prove directly that supernova shocks provide the acceleration only the analogy with electrons can be demonstrated. 

However, we observe what ought to be galactic cosmic rays up to energies near the knee, and beyond to the ankle, i.e., 3 EeV. 

FIGURE 2 The proton and helium spectra at low energy. [From Suzuki, T, ef al. (2000). Precise measurements of cosmic-ray proton and helium spectra with BESS spectrometer, Astrophys. J. 545,1135-1142 The AMS Collaboration. (2000). Protons in near earth orbit, Phys. Lett. 5472, 215-226 The AMS Collaboration. (2000). Helium in near earth orbit, Phys. Lett. 5494, 193-202.] 

One kind of evidence about where cosmic rays come from and what kind of stars and stellar explosions really dominate among their sources is the isotopic ratios of various isotopes of neon, iron, and other heavy elements these isotope ratios suggest that at least one population is indeed the very massive stars with strong stellar winds however, whether these stars provide most of the heavier elements, as one theory proposes, is still quite an open question. 

Antimatter as observed today can all be produced in normal cosmic ray interactions. However, even the detection of a single antinucleus of an element such as helium would constitute proof that the universe contains antimatter regions and would radically change our perception of the matter-antimatter symmetries in our world. 

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Abstract Results from direct and indirect measurements of cosmic rays are reviewed. Emphasis is given to the understanding of the knee in the energy spectrum. The data are compared to contemporary models for the knee. Implications on the present understanding of the origin of galactic cosmic rays are discussed. 

The study of galactic cosmic rays is perhaps more an exercise in taste than in visual appreciation. In fact we determine their composition without ever really seeing them. However, they constitute the only sample of matter in our possession that comes from outside the Solar System. The chemical and isotopic composition of this sample is measured using balloon- or satellite-borne particle detectors, since the Earth s atmosphere is fatal to them. When they slam into nuclei in the air, they fragment into tiny particles, thereby losing their original identity. 

Reeves H, Fowler WA, Hoyle F (1970) Galactic cosmic ray origin of Li, Be and B in stars. Nature 226 727-729... 

The solar system is filled with elementary particles of various origins. The dominant source is the Sun and we have extensively discussed in this chapter noble gases from the solar corpuscular radiation (Sun and Moon sections). Here we discuss galactic cosmic ray (GCR) particles, pick-up ions of interstellar or interplanetary origin, and anomalous cosmic rays. A recent overview is provided in a conference proceedings volume (Wimmer-Schweingruber 2001). A summary of the noble gas data is given in Table 13. 

Gamma-rays and cosmic rays from neutralino annihilation in galactic halos. We shift now our attention to signals originating in neutralino annihilations which occur in the halo of our galaxy or in the halo of external galaxies. 

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