The Role of the Ionospheric F2-layer Parameters in Occurrence of Mid- latitude Pi2 Pulsations
Abstract
We investigated the diurnal and seasonal fluctuations of the Pi2 occurrence rate and f0 F2 variations. We found that Pi2's are very frequently observed with small amplitudes or with a distorted form of the analog signal or are not observed at all during periods when there are abrupt changes of the ionospheric F2-layer critical frequency f0 in December (winter solstice). These times correspond to sunrise and sunset. For the period of summer solstice there is no evident suppression of pulsations because the F2-layer density remains virtually unchanging round-the- clock. It is possible to make the conclusion: the frequency of Pi2 pulsations appearance in the middle latitudes suffers seasonal variations during the day synchronically with the critical frequency f of ionosphere F2 layer. An abrupt0 change in electron density in the F2-layer, characteristic for sunrise-sunset, leads to suppression of Pi2 pulsations or produces specific conditions in the ionosphere which hamper their propagation to the point of observation in mid-latitudes. This fact should be taken into account when investigating global Pi2 pulsations in mid- latitudes
- Publication:
-
34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002cosp...34E2234R