Abstract:
Chang'E-1 and Chang'E-2 are 3-axis stabilized lunar orbiters with a circular polar orbit of an altitude of 200 km and 100 km respectively. The space environment system of Chang'E-1 and Chang'E-2 consists of two Solar wind ion detectors (SWIDs, SWIDA/B) and one high energetic particles detector (HPD). SWIDs were developed to measure the plasma environment around the Moon and the spectrum of the circumambient ions surround the spacecraft. The high energetic particles detector was designed to investigate the Solar energetic particles events and the energetic particles (proton, electron and heavy ions)in space. The basic charged particle environment nearby the lunar was obtained by the space environment system under the Solar minimum,weakly interplanetary magnetic fields(IMF) conditions. The results of the space environment system indicate that the energetic particles radiation environment near the lunar is the same as in the interplanetary when the lunar is in the Solar wind and the similar trend of variation is maintained when the Solar wind go through the interplanetary to the lunar. Hundreds of the bursts of 0.1~2 MeV energetic electrons(BEE)occurred by Chang'E-1 and Chang'E-2,and 20% of the ambient plasma ions accelerated on lunar orbit during BEE were observed when Chang'E-1 and Chang'E-2 flying through the terrestrial magneto sheath or the transition region of the boundaries. The results indicated that the BEE induced the surface potential increasing of the orbiter, and lunar or the spacecraft surface will charge to negative kilovolts during the BEEs after the temporal integral of the energetic electrons fluxes reach up to > 10
11 cm
-2 The complex interaction between Solar wind ions and lunar surface was observed,include the lunar sputter ions,reflection ions and Solar wind "pick up" ions.