Research To The Near-earth Energetic Particle Distribution And Short-term Solar Proton Event Forecast

Radiant condition of high energy particles at the outer space of the magnetosphere may have great influence on the human space activities. Solar proton events may bring hazard and danger to the satellites and spaceships that in the orbits near the earth, and may cause damage to the sensitive equipments on board the satellites. Thus precise description of the energetic particles environment and accurate prediction of the solar proton events especially short-term prediction are very important to assure the security of space task and coordinate the use of sensitive equipments.In this paper, the Understanding and research development of cosmic rays were discussed first. Then the relation between cosmic rays intensity and differential fluxes of space energetic proton and ion during quiet time was studied. Based on statistical analysis of the relation between neutron intensity and energy spectrum parameters, a new method was suggested to calculate the differential fluxes of proton and ion with high energy from neutron intensity measured by OULU neutron monitor. For particular discuss, four channels (350 - 420 MeV,420 - 510 MeV,510 - 700 MeV,> 700 MeV) on the GOSE satellite and the C element on the ACE satellite were chose as examples. Through comparison, it was concluded that the result was well consistent with the measurement. In order to prove the practicability of the method mentioned above in description of the space radiant condition, the differential proton fluxes were also calculated during November and December in 2006 by the method. As a result, it was concluded that the differential fluxes of space proton and ion might be well reverted from the intensity of the ground neutron with this method.For the solar proton event caused by solar eruption, the understanding and forecast research were summarized in this paper. The occurrence mechanism, spreading process as well as the hazard brought by bad space radiation environment were all discussed. Then according to the proton energy spectrum, the variation of energy spectrum parameters before the commence of SPE was analyzed in this paper with proton flux data from channel 4~9 MeV, 9~15 MeV, 15~40 MeV, 40~80 MeV on the GOES satellite. At last, a new method was introduced to use the variation of energy spectrum parameters and the proton flux data with energy >10MeV to predict SPE. The method was also used for SPE forecast at the five-year data selection in 2002-2006 by test. The result turned out to be encouraging with the accuracy rate reach to 97.5% and advance time of several tens minutes up to over a hundred hours.