An influence of IMF-By on the ion density planetary distribution during distrubed period 20–23 October 1981: Satellite and ground-based results

Abstract

The planetary distribution of the disturbed ion density (Ni) at fixed magnetic latitudes in both hemispheres, and in the evening and morning sectors, is examined using DE - B satellite and ground-based vertical sounding data. It is found that 1. the amplitude or (in some cases) the shape changes of the disturbed Ni longitude variations are asymmetrical in both hemispheres as well as in the morning and evening sectors; 2. the amplitude of “storm” variations is different at height of F2-layer peak and in the upper ionosphere (800–900 km); These irregularities in the ionospheric storm reaction are interpreted in terms of IMF influence on the magnetospheric convection pattern and its asymmetry - not only between evening and morning sectors in a given hemisphere, but also between northern and southern hemispheres. This hypothesis satisfactorily explains the different gradients of the equatorward wall of the trough and the lowest latitude reached by its minimum. The different statistical results concerning the positive and negative ionospheric storm effects, the isolated positive phase etc., can not be understood and correctly interpreted without reporting on the longitudinal variations of the ion density during magnetic disturbances and their specific manifestations.