A Statistical Study of Intense High-Altitude Electric Fields Using Cluster

The occurrence and characteristics of intense (≥150 mV/m, mapped to the ionosphere) electric fields at high altitudes (4-7 R_E) are investigated in a statistical study using data from the Cluster satellites. The 36 months of EFW data used from four satellites give a good database for statistical interpretations. The relation of the events to MLT, Ilat, altitude and other parameters are investigated. An attempt to distinguish between divergent and convergent potential structures is made. The relation of the intense electric field events and up- and down-going currents is analyzed. Although the satellites at this stage in the investigation are considered as single point measurements, the possibilities of a four-point statistic are tempting.