Cosmic Ray Anisotropy and the Knee of the Energy Spectrum

Abstract

The knee of the cosmic:ray energy spectrum occurs at an energy slightly below 10 1 6 eV. At a similar energy significant changes are found in cosmic ray shower development and anisotropy. It is suggested that these changes can be understood if there is a general proton dominated cosmic ray flux along our spiral arm from outer galactic regions, which is exceeded by an iron dominated flux from the opposite spiral arm direction at energies between~10 1 4 and~10 1 7 eV.

Cosmic Ray Anisotropy below 1015 eV

“…1 might still be compatible as discussed by Clay (1984) since cosmic ray streaming along a particular direction (in this case close to the direction of our spiral arm) results in a maximum intensity in the upstream direction and a minimum in the downstream direction. Since the first harmonic of the anistropy is quoted in terms of the direction of the maximum of a fitted sine wave, a mInImUm in a downstream direction would be reported as a maximum 180° away at a certain latitude/declination.…”