ISSN 1002-1027　　CN 11-2952/G2

### Energetic Particle Event Observed by a Polar Orbit Satellite at 780km

ZOU Hong1, XIAO Zuo1，WU Zhongxiang2, ZHU Wenming2

1. 1Department of Geophysics, Peking University, Beijing, 100871, E-mail: zxiao@pku.edu.cn；2Institute of Spacecraft System Engineering, Beijing, 100086
• Received:2002-05-30 Online:2003-05-20 Published:2003-05-20

Abstract: The first set of data collected by the energetic particle detectors on board of the ZY-1, a China Brasilia coordinated earth resource satellite, were introduced briefly in this paper. ZY-1 is a polar orbiting satellite at an altitude of 780km and launched on 14th October 1999. This is the first time that such measurement is carried out inside a satellite cabin. For the purpose of statistics, a consecutive set (around at least 3 to 5 times) of distinguishable records of electrons or protons was defined as a particle event. The preliminary analysis shows that almost all of the events recorded are located at polar and South Atlantic regions (SAA). In the northern polar region, at the same longitudes of SAA, there is a clear gap of occurrence of flux events. Proton events in general only occur in SAA region while electron events appear at both SAA and polar regions.Electron flux of 0.5～2.0MeV in polar regions is dominant over that of 2～15MeV，while at SAA, fluxes from the two channels are about the same. There is a close correlation between energetic particle radiation inside and outside the satellite.