Anatoly D. Erlykin

On the nature of the correlation between cosmic-ray intensity and cloud cover

Various aspects of the connection between low cloud cover (LCC) and cosmic rays (CRs) are considered. Most features of this connection point to the absence of substantial causal relationship between LCC and CRs. Even on the assumption that some LCC fraction is related to CR intensity and varies with it, its most likely value is about 2% (although, within two standard deviations it can be as high as 20%). The most serious argument against the causal relationship between CRs and LCC is the existence of negative correlation between low and medium cloud cover (MCC). The scenario of simultaneous influence of solar activity on CRs and cloud cover is discussed, which might lead to the observed correlations.

A look at the cosmic ray anisotropy with the nonlocal relativistic transport approach

The Cosmic Ray anisotropy is a key element in the quest to find t he origin of the enigmatic particles. A well known problem is that, although most of the likely sources are in the Inner Galaxy, the direction from which the lowest energy particles (less t han about 1 PeV) come is largely from the Outer Galaxy. We show that this can be understood taking into account a possible reflection of charged particles by ’walls’ in the Interstellar Medium or/ and as a temporary phenomenon after the shock wave from the supernova explosion passed the Earth. This effect is too subtle to be explained by an ordinary diffusion theory and becomes apparent within the frames of the non-local relativistic transport theory, which involves conception s of free motion velocity and path lengths with probability distributions of non-exponential type ta ken for a turbulent interstellar medium.

An anomaly in the properties of primary cosmic rays from the Vela cluster

Based on experimental data obtained by the GAMMA array for the knee energy region, an anomaly is found in the mass composition of primary cosmic rays arriving from the region of the Vela cluster. An original difference method is used that offers high sensitivity, protection against accidental experimental errors, and the ability to separate anomalies associated with the laboratory coordinate system from those in celestial coordinates. Allowing for the multiple scattering of charged particles in the galactic magnetic fields allows parts of the sky not directly visible from the array to be studied.

Characteristics of the energy spectra of cosmic rays and a single source model

As the accuracy of measuring the energy spectra of different nuclei in the primary cosmic ray flux and their ratios grows, more evidence appears for the nonpower character of these spectra at energies below the knee at 3–4 PeV. Irregularities in the spectra are the natural consequence of the nonuniformity of the cosmic ray source distributions: their types, ages and distances to the Earth; the nonuniformity of the interstellar medium; and the different densities, temperatures, and natures of magnetic fields. In particular, the flattening of the proton and helium energy spectra, the growth of the fraction of positrons in the total flux of positrons and electrons, and the constancy of the ratio of antiprotons to protons at sub-PeV energies could be due to the contribution from nearby and young sources emitting harder energy spectra of particles. It is shown that the recent measurements of the ratio of the boron and carbon nuclei performed in the AMS-02 experiment could also indicate that there is a contribution from a single comparatively young and nearby source.

Vela as the source of cosmic rays responsible for the formation of the knee in their energy spectrum

The sharpness of the knee in the cosmic ray (CR) energy spectrum observed at energies of 3–4 PeV could be due to the contribution from a relatively young and nearby single source. Using models for the acceleration and propagation of CRs in the Galaxy allows the limits on the distance to the source and its age to be estimated. The Vela cluster is shown to lie within these limits. Additional arguments based on the anisotropy and structure of the CR energy spectrum at PeV and above are presented in favor of Vela as one such single source responsible for the formation of the knee.