No abstract

Solar energetic particles acceleration by a shock wave accompanying a coronal mass ejection (CME) is studied. The description of the accelerated particle spectrum evolution is based on the numerical calculation of the diffusive transport equation with a set of realistic parameters. The relation between the CME and the shock speeds, which depend on the initial CME radius, is determined. Depending on the initial CME radius, its speed, and the magnetic energy of the scattering Alfvén waves, the accelerated particle spectrum is established during 10-60 minutes from the beginning of CME motion. The maximum energies of particles reach 0.1 -10 GeV. The CME radii of 3 -5 R ⊙ and the shock radii of 5 -10 R ⊙ agree with observations. The calculated particle spectra agree with the observed ones in events registered by ground-based detectors if the turbulence spectrum in the solar corona significantly differs from the Kolmogorov one.

A theory of the formation of Forbush decrease in a magnetic cloud is presented. It is found that the formation mechanism is the energy loss of cosmic rays in a magnetic cloud represented as a moving magnetic loop with a helical field. The Forbush decrease amplitude, the components of the vector, and tensor anisotropies are calculated along the path of the magnetic cloud passing Earth. It is shown that the Forbush decrease characteristics depend on the following magnetic cloud parameters: magnetic field strength, the helical field structure, velocity and the velocity gradient, and geometric dimensions. It is found that the Forbush decrease characteristics mainly depend on the magnetic field strength and the state of the global helical structure of the field.

No abstract

No abstract