Conditions of Intense Precipitation of Energetic Particles near the Boundary of Closed Drift Shells in the Earth's Magnetosphere Described by the Tsyganenko-89 Magnetospheric Model

摘要

Conditions of energetic particle motion at outer closed drift shells in the Earth's magnetosphere, described by the Tsyganenko-89 model, have been considered for K_p = 1, 3, and 5. The method of central trajectory, previously used to anlayze particle motion in a dipole field, is applied. The χ = ρ_L/R parameter has been selected in order to characterize a particle. It has been obtained that, at the same geomagnetic latitudes, the χ value for particles with a certain momentum is higher than in the dipole field on the nightside and is lower on the dayside. At χ = χ_(dip), the scattering angle of particles moving along a field line is higher than in the dipole field on the nightside and is lower on the dayside. The χ_(cr) value, at which the scattering angle at the equator is equal to the loss cone angle, has been selected as a quantitative criterion of particle motion adiabaticity. The particle scattering at a drift trajectory has been calculated as a function of the magnetic local time. Results of calculation explain the location of the penetration boundary for low-energy cosmic rays and the structure of the outer belt near its boundary.