Focusing on the classification of solar winds into three types of flux: (1) slow winds, (2) fluctuating winds, and (3) high speed-solar winds HSSW (V ≥ 450 km/s on average day), the influence of the convection electric field (E M ) via the flow of HSSWs during storms in the internal magnetosphere and on the stability of magnetospheric plasma at high latitudes was investigated. The study involved 1964-2009 period, which encompasses solar cycles 20, 21, 22 and 23. The results show a weak correlation of the frozen electric field profiles with the HSSWs overall solar cycles and a very large number of HSSWs recorded in cycle 23. Particular attention has been paid to solar cycle 22 which rather presents a fairly disturbed profile with sudden variations in solar flux and E M field; however, solar cycle 21 records the lowest level of HSSW. Overall, over all the studied solar cycles, it can be seen that the E M field from HSSWs of very low intensity increases progressively from solar cycle 20 to cycle 23, respectively with a minimum occurrence of 8.48% and a maximum of 9.36%. The results reached show, on one hand, that the magnetosphere is very stable from 15:00UT to 21:00UT, and on the other hand, that there is a significant transfer of mass in the night sector (21:00UT-24:00UT) than on the day side (00:00UT-15:00UT) for all solar cycles over the long period of 45 years.

https://academicjournals.org/journal/AJEST/article-full-text-pdf/07F381E68408.pdf

Variability of the magnetospheric electric field due to high-speed solar wind convection from 1964 to 2009

Earth's magnetosphere is a magnetic shield that protects the Earth from the energetic emissions of the high-speed Solar Wind (HSSW). We perform a statistical analysis of the response of Earth's magnetosphere inner part under the impact of HSSW over 40 years of data encompassing solar cycles 20-23. With misidentified events or events interacting with interplanetary coronal mass ejections (ICMEs) removed, only 23552 events were identified. The results we obtained show that more than 85% of the events recorded from 1964 to 2009 are generated by coronal holes (CHs). Almost all observations were confined between 250-800 km/s and show a unimodal distribution per solar cycle: (1) 93% of the solar wind (SW) velocities are on the order of 567.77 ± 2.46 km/s for solar cycle 20, (2) 81% of the SW velocities are worth 524.30 ± 2.69 km/s for cycle 21, (3) 92% of the SW velocities progress to 565.15 ± 2.72 km/s for cycle 22, and (4) 75% of the SW velocities show a value on the order of 530.38 ± 2.22 km/s for cycle 23. Furthermore, our analysis shows a lower electron density at the beginning of the cycle (48%) than at the end of the solar cycle (52%). Thus HSSWs are more frequent at the end of solar cycles, while the magnetospheric electric field (EM) instead shows dominant features during the upward phase of odd cycles and the downward phase of even cycles. Therefore, the stability of the inner magnetosphere is more significant during the decline of solar cycles.

Geoeffectiveness of the inner magnetosphere under the impact of fast solar wind currents: Case of solar cycles 20 to 23

The Earth’s magnetosphere is a magnetic shield that protects Earth from high-energy particles and is subject to a series of internal processes caused by jets of the solar wind (SW) that destabilize it. These disturbances affect health as well as technology and become more extreme when SW is more accelerated. Thus, to better understand the impact of high-speed solar wind (HSSW) invasion on the dynamics of the magnetospheric system, a statistical study of HSSW populations was conducted for even (20 and 22) and odd (21 and 23) solar cycles. The regression analysis using the solar-derived fields from all solar cycles, indicates three states of the inner magnetosphere: 1) the 00:00UT-15:00UT period marked by a magnetic reconnection on the day side of the Earth closest to the Sun with the interplanetary magnetic field (IMF) facing South; 2) the 15:00UT-21:00UT period where IMF changes from South to North and remains there until 21:00UT; and 3) the 21:00UT-24:00UT period where there is a reconnection on the night side with stretched field lines. Observations made at different phases of solar activity lead us to suggest that the magnetospheric electric field (EM) and the Bz component of IMF (IMF-Bz) are strongly correlated not only at a particular time scale, but at different time scales. We believe that the daily fluctuations of the electrical and magnetic effects of magnetospheric origin currents play a very important role in the dayside magnetic reconnection rate. Moreover, examination of the cycles with different parities shows important amplitudes of the solar causes for the even cycles compared to the odd solar cycles. Therefore, even solar cycles have a strong influence on our socio-economic system compared to odd cycles. 

Energetic Dynamics of the Inner Magnetosphere in Contact with Fast Solar Wind Currents: Case of the Period 1964-2009

The signatures of the geoeffectiveness solar disturbed events on the Magnetosphere Convection Electric Field (MCEF) universal time variation from 1964 to 2009 are investigated. Here, attention is focused our on the periods concerned by the whole shock activity and by the different types of the geoeffectiveness Coronal Mass Ejections (CMEs) which are one-day-shock, two-days-shock and three-days-shock. The investigation is made with respect to the orientation of the Interplanetary Magnetic Field (IMF). The MCEF time profiles show three different trends except for one-day-shock activity and for three-days-shock activity where we have four trends and one trend, respectively. The MCEF time profiles of the whole disturbed activity, the all shock activity and the one-day-shock activity present the initial phase where the Interplanetary Magnetic Field (IMF) is southward. During the two-days-shock activity, the initial phase of the MCEF shows a non-sensitive trend to the change of the direction of the IMF z-component while for the three-days-shock activity, the MCEF always exhibits the signature of the northward IMF. The last trend of the MCEF time profile shows the southward IMF signature except for the one-day-shock and the three-days-shock activities where that of the northward IMF was seen.

	Key words: Magnetosphere convection electric field, interplanetary magnetic field, shock activity, coronal mass ejections (CMEs).

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Magnetosphere convection electric field (MCEF) time variation from 1964 to 2009: Investigation on the signatures of the geoeffectiveness coronal mass ejections

Ouattara Frederic

Papers

Magnetosphere convection electric field (MCEF) time variation from 1964 to 2009: Investigation on the signatures of the geoeffectiveness coronal mass ejections