Michael E. Katz

Variations of cosmic-ray energy in interplanetary space

A consistent theory of energy exchange between high-energy charged cosmic-ray particles and the random inhomogeneities of a magnetic field frozen in the moving solar wind plasma is developed. It is shown that the mode of the particle energy variations at a given law of plasma velocity variation in space is determined by the specific form of the particle distribution function. The equation for the density of cosmic-ray energy is obtained. Consideration is given to the generation of a charged particle energy spectrum in the course of multiple scatterings by the random inhomogeneities of the magnetic field.

Cosmic-ray propagation in inhomogeneous large-scale magnetic fields: A pitch-angle diffusion and convection

A drift kinetic theory of cosmic-ray (CR) propagation in inhomogeneous random large-scale magnetic fields (MF) is considered. An averaging of the drift kinetic equation for CR particles distribution was performed in the statistical ensemble of MF realization, whereby the curvature radius of randomly wandering MF is much larger than gyro-radiusRH of CR particles. Collisions of CR particles on the small-scale MF inhomogeneities with the characteristics scalelO ≪RH is not taken into account. It is proved that this random MF raises non-zero pitch-angle diffusion of the CR particles, which is very strong for particles with zero pitch angle. The transport equation is derived for a case of weak inhomogeneity of the random MF in the direction of MF mean value. In this case additional convection of particles in the direction of energy density gradient of random MF variables.

Cosmic-ray fluctuations in interplanetary space

Cosmic-ray (CR) fluctuations in both the drift and diffusion approximations are investigated and the results compared with experimental data. Kinetic equation is used to obtain equations for the second moment of the CR distribution function (the correlation function of the distribution function fluctuations) in both approximations. An application of these approximations to the correlation function equation gives the relations between the CR power spectra and random magnetic fields in interplanetary space. Different magneto-turbulence models are taken in consideration and the relations between the spectral indices are obtained in various frequency intervals.The theoretical results are compared with experimental data obtained by the network of neutron monitors. The CR power spectra observed at the ground level during the years 1978–1981 has been calculated. The investigated frequency range of 3×10−8 to 10−4 Hz consists of two parts, with a ‘transient’ region of 10−6 to 10−5 Hz. Together with the ‘background’ CR fluctuations the contribution of both the periodic and aperiodic phenomena is observed.

COSMIC-RAY ANISOTROPY IN INTERPLANETARY SPACE

The kinetic equation describing cosmic-ray propagation in interplanetary space has been used to construct a consistent theory of cosmic-ray anisotropy including the second spherical harmonic of particle angular distribution. The amplitude and phase of semi-diurnal cosmic-ray variation have been calculated. Expressions describing the relationships of the semi-diurnal variation parameters to helio-latitude distribution of cosmic rays have been derived. The results obtained are compared with observational data.