Composition and Spectra of Primary Cosmic-Ray Electrons and Nuclei above 1010 eV
Abstract
Recent experiments have extended the knowledge of the flux and energy spectra of individual cosmic-ray components to much higher energies than had previously been accessible. Both electron and nuclear components show a behaviour at high energy which is unexpected, and which carries information regarding the sources and the propagation of particles between sources and observer. Electromagnetic interactions which are suffered by the electrons in interstellar space should steepen their spectrum, a steepening that would reveal the average lifetime a cosmic-ray particle spends in the galaxy. Measurements up to 1000 GeV show no such steepening. It was discovered that the composition of the nuclear species which is now measured up to 100 GeV/nucleon changes with energy. This change indicates traversal of less interstellar matter by the high energy particles than by those of lower energy. We discuss the experimental evidence and its implication.
- Publication:
-
Philosophical Transactions of the Royal Society of London Series A
- Pub Date:
- January 1975
- DOI:
- 10.1098/rsta.1975.0003
- Bibcode:
- 1975RSPTA.277..349M
- Keywords:
-
- Astronomical Models;
- Chemical Composition;
- Energy Spectra;
- Heavy Nuclei;
- Primary Cosmic Rays;
- Abundance;
- Electromagnetic Interactions;
- Electron Emission;
- Energy Dissipation;
- Galactic Radiation;
- Interstellar Radiation;
- Nuclei (Nuclear Physics);
- Particle Energy;
- Particle Flux Density;
- Space Radiation;
- ASTRONOMICAL MODELS;
- CHEMICAL COMPOSITION;
- ENERGY SPECTRA;
- HEAVY NUCLEI;
- PRIMARY COSMIC RAYS;
- ABUNDANCE;
- ELECTROMAGNETIC INTERACTIONS;
- ELECTRON EMISSION;
- ENERGY DISSIPATION;
- GALACTIC RADIATION;
- INTERSTELLAR RADIATION;
- NUCLEI (NUCLEAR PHYSICS);
- PARTICLE ENERGY;
- PARTICLE FLUX DENSITY