Latitude Variation of Peak E, Occurrences during a Half-Solar Cycle

Abstract

The results of the variation of the peak occurrence (evaluated as percentage) of sporadic-E during an ascending half-solar cycle with geomagnetic latitude are reported. It is seen that E_s occurrence is maximum in low sunspot period for low and middle latitudes, and vice versa for equatorial and high latitudes. The southern latitudes, in particular, show a systematic decrease in E, occurrence with increase in geomagnetic latitude for all limiting frequencies of E_s (<i>f</i>E_s). An attempt is made to explain the above results on the basis of the <i>S_q</i> current system.