Night-time sporadic E measurements on an oblique path along the mid-latitude trough at sunspot minimum and sunspot maximum

摘要

Results are presented of the night-time occurrence of sporadic E on a path tangential to the mid-latitude trough under conditions of sunspot maximum and sunspot minimum, and for different levels of geomagnetic activity. Sporadic E was observed more often at sunspot minimum and when kp was high (≫5). For kp≤5, at sunspot minimum sporadic E is observed less frequently with increasing kp, while the opposite is the case at sunspot maximum.