The spectrum of solar relativistic cosmic ray measurements and numerical simulation

[摘要] The solar relativistic protons are measured with the worldwide network of neutron monitors. The big pulses of relativistic protons appeared after the flares occurring in the West side of the Sun disk. They arrive to the Earth along Archimedean magnetic lines without collisions in ∼15 min after a flare. This prompt anisotropic flux contains information about the exponential ∼exp(-E/E0) spectrum of protons ejected from the solar cosmic ray source. After delay of 15 - 20 min the proton flux becomes isotropic with power spectrum E-γwhere γ ∼ 5. Apparently, beam instability is developed. The protons accelerated in eastern flares can reach the neutron monitor due to diffusion across the magnetic lines. The magnetic field energy accumulation in the current sheet in the solar corona above the active region is proved by MHD simulations and the position of observed flare thermal X-ray source. During a flare the magnetic field energy is transferred into the particle energy. Proton acceleration up to relativistic energy can occur in the electric field applied along the singular line in a current sheet. The electric field E = -V×B/c is created due to the fast rate of reconnection V. At typical V = 2×107cm/s the measured spectrum coincides with the calculated spectrum.

[发布机构] Lebedev Physical Institute RAS, Moscow, Russia^1;Institute of Astronomy RAS, Moscow, Russia^2;Polar Geophysical Institute KSC RAS, Apatity, Russia^3;Institute for Solar-Terrestrial Physics SB RAS, Irkutsk, Russia^4

[效力级别] 天文学 [学科分类] 天文学(综合)

[关键词] Beam instability;Calculated spectrum;Cosmic ray sources;Magnetic field energy;Neutron monitors;Proton acceleration;Relativistic energy;World-wide networks