Proton acceleration in the solar flare

Abstract

Hundred years of cosmic ray investigations have not lead to the ultimate understanding the mechanisms of particle acceleration. Most popular theoretical mechanisms of solar comic ray generation are associated with shock waves. The discovery of sources of protons with relativistic energies, generated by the Sun (solar cosmic ray), gives us hope for the opportunity to clarify the mechanism of cosmic rays generation. The important information about the mechanism of proton acceleration in the Sun has been obtained from results by GOES of measurements. The association of a proton event with a particular flare is beyond doubt. The GOES measurements indicate propagation of the high-energy protons front without collisions from the flares that appeared on the western part of the solar disk. These protons can move along the helical magnetic field lines to the Earth. The protons from flares on the back side of the Sun can also come to the Earth's magnetosphere along magnetic lines. Protons from eastern part of the solar disk can come to the GOES across the magnetic lines. The front of the proton flux from eastern flares comes to Earth with a delay of several hours. The series of 2–3 weeks long proton events produced by several proton flares are observed one - two times in the 11 year cycle of solar activity. Nature of a trigger for initiating such series of proton events is not clear.