Observation of the interplanetary and solar parameters in major solar-energetic particle fluxes

The hourly solar energetic particles (SEP) and interplanetary (IP) measurements for the three considered-largest SEP events have been compared. The study determined the most relevant physical factors which determine the largest SEP properties. The particle-intensity increases that are observed around the time of the shock passage are composed not only of particles locally accelerated at the shock region by the strong disturbances of the magnetic field, but also of particles previously accelerated by different mechanisms around the shock. Following the IP shock passage, the solar plasma tended to be more dense, cooler and faster than at the boundary regions of the shock. The rate of geomagnetic disturbances during 14-19 July 2000 was stronger than the other events and included high changes. In contrast, the third event of 9 November 2000 was not shed a ground level enhancement (GLE). Fast rise and long decay in particle intensities which may be originated from different sources on the sun. Keywords: Solar energetic particles; the ground level enhancements; the particle-acceleration in the heliosphere; the interplanetary and solar parameters; the geomagnetic disturbances