1.2.1. Internal and external CR of different origin
As was considered in Dorman (M2004, Section 1.1.1), it is natural to define CR as particles and photons with energies at least several orders of magnitude higher than the average energy of thermal particles of background plasma. There are internal CR, generated inside the background plasma of some object, and external CR, generated in other objects and propagated into the object considered. For example, metagalactic (or extragalactic) CR of very high energy (up to 1021eV), are generated in radio galaxies, quasars and other powerful objects in the Universe, and come through intergalactic space to our Galaxy, to the Heliosphere, and into the Earth's atmosphere. Therefore they are internal CR relative to the Metagalaxy and external CR relative to the Galaxy. Galactic CR with energy at least up to 1015 ■ 1016eV, generated mainly in supernova explosions and supernova remnants, in magnetospheres of pulsars and double stars, by shock waves in the interstellar space and other objects in the Galaxy, are internal relative to the Galaxy and external for Heliosphere and the Earth's magnetosphere. Solar CR with energy up to 15 ■ 30 GeV, generated in the solar corona in periods of powerful solar flares, are internal for the Sun's corona and external for interplanetary space and the Earth's magnetosphere. Interplanetary CR with energy up to 10 ■ 100 MeV, generated by terminal shock wave on the boundary of the Heliosphere and by powerful interplanetary shock waves, are internal for the Heliosphere and external for the Earth's magnetosphere. Magnetospheric (or planetary) CR with energy up to 10 MeV for Jupiter and Saturn, and up to 0.030 MeV for the Earth, generated inside the magnetospheres of rotated magnetic planets, are internal in magnetospheres of planets and external in the interplanetary space.
1.2.2. On the main properties of primary and secondary CR
The main properties of primary CR, according to measurements by balloons in the upper atmosphere and by satellites outside the atmosphere and magnetosphere (protons and nuclei with different charge Ze, electrons and positrons, anti-protons and gamma rays) were considered in detail in Dorman (M2004, Section 1.4). Below in Sections 1.2.3—1.2.13 we will consider shortly main properties of observed energy spectrum, anisotropy, transport paths, and chemical composition of galactic
CR and show that they are in close relationships caused by peculiarities of CR interactions and propagation in space plasmas which will be considered in the remaining part of Chapter 1 and in Chapter 2.
properties of secondary CR (neutrons, protons, pions, muons, electrons, positrons, gamma rays, neutrinos, etc.) generated in nuclear meson and electromagnetic cascades in the Earth's atmosphere as a result of interactions of primary CR with the nucleus of atmospheric atoms (and for neutrinos also as generated in the solar interior) were considered in detail in Chapter 2 of the book Dorman (M2004). Below, in Section 1.3 we will consider CR interactions with the matter of space plasma, nuclear reactions, fragmentations, and generation of secondary elementary particles and daughter nuclei in the space plasma.
1.2.3. Five intervals in the observed CR energy spectrum
According to Dorman (1977a,b,c), the observed CR spectrum near the Earth's orbit can be broken into five intervals (see Fig. 1.2.l): 1 — kinetic energy interval 1021 eV> Ek > 3x1015 eV, 2 — 3x1015eV> Ek > 3x10n eV, 3 — 3x10u eV> Ek > 30 MeV/nucleon ,4—30 MeV/nucleon > Ek > 1 MeV/nucleon, 5 — Ek < 1 MeV/nucleon. Such a division in Fig. 1.2.1 is based on some physical considerations and observation data.
Fig. 1.2.1. The observed CR spectrum broken into five energy ranges. The shaded area shows the region subjected to solar modulation. According to Dorman (1977a).
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