F-region oscillations observed during October 24, 1995 solar eclipse at Waltair

Abstract

Measurements of changes in phase path/Doppler of HF signals on 5.5 MHz from F-region of the ionosphere are carried-out using coherent pulsed Doppler radar. Preliminary analysis of the data show large deviations in phase path centered around the time of maximum phase of the eclipse on the eclipse day when compared to the control days. These deviations in phase path exhibit a long period oscillatory pattern comparable to the duration of the eclipse with the maximum aptitude during the eclipse interval. The same is severely damped during post eclipse intervals. Enveloped with this long period damped oscillation a systematic short period oscillatory pattern is observed in phase path after the last contact. The periodicity of these short period components are of the order of atmospheric gravity waves with pronounced periods of about 12 minutes followed by 17 and 30 minutes, immediately after the last contact.