Measurements of upward electron beams and ion conics from the polar orbiting Viking satellite have been obtained in the cusp-cleft region. The relative frequencies of occurrence have been calculated for studies of the MLT, Inv. Lat., and altitude distribution during the period March to June 1986. It was observed that the upward electron beams were more frequent in the dawn sector compared to the dusk sector. Similar observations have also been seen for the ion conics.

The Invariant Latitude dependence of upflowing electron beams shows a clear maximum around 78¿. This agrees well with the maximum for ion conics.

The altitude dependence shows a steep increase in frequency above 10 000 km up to the satellite apogee (≈13 500 km). This altitude dependence at different AE index was also studied giving information about the acceleration region and the altitude profiles at different levels of magnetic disturbance. ¿ American Geophysical Union 1991