A high-latitude, earth-based high-frequency (9.9MHz) radiowave backscatter technique for the real-time detection of Long Delayed Echoes was tested at College, Alaska. Over 2000 apparent LDE were detected and recorded from 15 to 22 July, 1980. A positve correlation was obtained between the number of reflections per unit time and the probable entry of enhanced solar plasma into the magnetosphere and/or local disturbed magnetic conditions. The modes and paths by which the signals propagate are yet to be established. However, regardless of their origin, the echoes seem to be qenuine and these observations are therefore unique in the study of LDE radiowave propagation phenomenology. |