O + and He + restricted and extended (BI‐modal) ion conic distributions

We have developed an automated procedure using standard image processing techniques that finds and characterizes energetic ion conic events in the data acquired by the Energetic Ion Composition Spectrometer on DE‐1 in the altitude range 8,000 to 24,000 km. The algorithm discriminates between the two types of ion conic distribution, those restricted to a narrow angular range and those extended in angle. Extended (bi‐modal) ion conic distributions also have a significant flux of field‐aligned energetic ions. Extended ion conies constitute more than one third of the ion conics found. The two types of ion conic distribution have different altitude dependences. The average properties of energetic conic distributions suggest that conic formation by localized, explosive, transverse energization is not the dominant mechanism responsible for producing energetic conic distributions above 8,000 km.