Abstract

This paper compared the signatures of shock activity and magnetic clouds (caused by geoeffective interplanetary coronal mass ejections (ICMEs)) on the diurnal variability of the magnetospheric convective electric field (MCEF) from 1996 to 2019. The investigation is done as a function of the orientation of the interplanetary magnetic field (IMF). The temporal variabilities of the MCEF of the two geomagnetic activities are different but both show a dependence on the phase of the solar cycle. For a given phase, the daily mean value of the MCEF on shock days is higher than on magnetic cloud days. Similarly, at all times, at phase minimum and at the falling phase, the hourly MCEF values during shock days are higher than those during days of magnetic cloud activity. The same result is observed in all phase periods (regardless of the phase). At phase minimum, there is a night reconnection during shock days, whereas during magnetic cloud activity days the MCEF ends the day with a northward oriented IMF.  At phase maximum, there is magnetic reconnection at the lobes of the Earth's magnetosphere for both types of activity. During the downward phase there is (1) reconnection at the magnetospheric lobes in days of shock activity (2) the IMF maintaining a southerly direction from 1000 UT to 2400 UT.

Key words: Magnetosphere convection electric field, interplanetary magnetic field, interplanetary coronal mass ejections, shock activity, magnetic cloud activities.