Low altitude ENA emissions observed from various vantage points on IMAGE

Interaction between the atmosphere and proton precipitation from the ring current results in proton ENA emission into space, due to an effective reflection from the atmosphere. Observation of this emission from the orbiting IMAGE spacecraft is strongly dependent upon the location of the spacecraft, because the emission is non-isotropic and the flux of reflected ENAs is therefore non-homogeneous in space. We have presented observations of reflected ENAs taken when IMAGE was at relatively low altitude. In this paper we will present results from a wider range of IMAGE altitudes. We present latitude distributions of the reflected ENA source along with estimates of the pitch angle distributions at the source location. We will discuss these results in terms of the reflection process and what we can learn about the proton precipitation by studying the reflected ENA distributions.