Auroral particle instrument onboard the index satellite

The INDEX satellite is a microsatellite which will be inserted into a low-altitude (680 km) polar orbit. A low-energy plasma particle instrument, which consists of two sensor heads (electron/ions sensors;,ESA/ISA) and a multi-spectral auroral camera (MAC) will be installed in the INDEX satellite in order to investigate formation mechanisms of fine-scale structures of optical auroral arc emissions. One of advantages of the INDEX mission is that the satellite is capable to observe fine-scale auroral arc emissions and corresponding auroral particles simultaneously by controlling an attitude of the satellite. Since the satellite velocity is relatively fast, a high time-resolution is necessary for the plasma measurement. The time resolution of the plasma instruments onboard the INDEX satellite is 20 ms, which corresponds to a spatial scale of ∼150m.