Paper#: 9
Poster #: 10
Session Name: Poster Session 1
Room: East Ballroom
Day: Tuesday
Time: 10:10 a.m.-Noon
Abstract Title: Pre-substorm Delta of F2 Increase in the Ionosphere
PresentSurname: Blagoveshchensky, D.V.
All Authors: D.V. Blagoveshchensky
Abstract : In this paper the main attention will be given to the Earth’s ionosphere processes preceding to the onset of an isolated substorm (moment To) , in particular, to positive splashes of foF2 (DELTAfoF2>0) 6-8 hours before To which are observed by ionosondes in Europe irrespective of the polarity of substorms (positive or negative). Results of such analysis could be useful for developing of algorithms of substorm onset forecasting with 2-3 hours ahead To. It is very important for problems of solar-terrestrial physics, space weather, wave propagation and so on. It is known that there are diffuse and intermediate particles with V>Vsw before the interplanetary shock. These particles can occur in the cusp region ~6 hours before the substorm onset To. Within this time heating of the noon cusp ionosphere begins and disturbed wind appears including the equatorward wind. The geomagnetic field can stay practically quite. Because heating is mainly located at the F-region heights the increase of the ionization takes place mainly in the F-region of the cusp and southward. The particles participated from the entry layer of the magnetosphere can be an additional source of the enhanced ionization of the auroral zone. Thus, the possible mechanism of formation of positive peaks of DELTAfoF2 6-8 hours before To was considered. The main feature here is the definitely other channel of the solar wind energy penetration into the ionosphere through the diurnal cusp as distinct from the classical channel through the magnetospheric tail, plasma sheet and the auroral ionosphere.