The Dynamic Distribution Feature Of Energetic Proton Flux In South Atlantic Anomaly

The Radiation belt is one of the most important regions in Earth’s magnetosphere. The geomagnetic disturbance has a great negative influence on the space shuttles and their relative space activities which occur in the low Earth orbit (LEO). As the outstanding region in the inner radiation belt, South Atlantic Anomaly (SAA) is the most typical and important research target.This article uses19-27MeV energetic proton flux data observed by SAMPEX from1992to2004to study the distribution feature of energetic proton flux in SAA. We discuss and compare different ways about mapping the energetic proton flux based on the data, display the long evolutionary process of the distribution of energetic proton flux by data classification, and fit the19-27MeV energetic proton flux data in different ways. We find that changes of F10.7index and altitude have a great influence on the distribution feature of energetic proton flux in SAA. During geomagnetic quiet times at540(±25)km, energetic proton flux in SAA decreases with the increasing of F10.7index. According to the statistical analysis of SYM-H<-50, we find that there is an obvious anti-correlation between energetic proton flux in SAA and the absolute value of SYM-H index. During the main phase of geomagnetic storms, the energetic proton flux is significantly reduced. In the recovery phase, the energetic proton flux shows a substantial sign of recovery. At the end of this paper, we also discuss the feasibility of modeling the energetic proton flux of SAA during the magnetic storms.