Solar–geomagnetic activity and Aa indices toward a standard classification

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

“…The shock activity days are determined by means of the pixel diagrams ( Figure 1) carried out by using the aa daily values (Ouattara and Amory Mazaudier, 2009). These diagrams highlight the repartition of the geomagnetic data as a function of the solar activity as described by solar rotation (27 days) (Ouattara and Amory Mazaudier, 2009;Gyébré et al, 2015).…”

“…The shock activity days are determined by means of the pixel diagrams ( Figure 1) carried out by using the aa daily values (Ouattara and Amory Mazaudier, 2009). These diagrams highlight the repartition of the geomagnetic data as a function of the solar activity as described by solar rotation (27 days) (Ouattara and Amory Mazaudier, 2009;Gyébré et al, 2015). The four geomagnetic classes of activity [(1) quiet activity due to the slow solar wind, (2) recurrent activity caused by the high stream solar wind, (3) fluctuating activity provoked by the fluctuating solar wind and (4) shock activity that results from the action of the geoeffectiveness CMEs (Coronal Mass Ejections)] as defined by Legrand and Simon (1989), Simon and Legrand (1989), Richardson et al (2000) and Richardson and Cane (2002).…”

“…Several authors , 2000;Richardson and Cane, 2002;Ouattara and Amory Mazaudier, 2009) showed that the geomagnetic storms [defined as global magnetic disturbances that result from the interaction between magnetized plasma propagating from the Sun and magnetic fields in the near-Earth space environment (Tommaso et al, 2016)] can be due to (1) recurrent activity (due to solar high stream wind coming from coronal holes), (2) shock activity (produced by the geoeffectiveness CMEs) and (3) fluctuating activity (caused by the geoeffectiveness fluctuating solar wind provoked by the fluctuation of solar neutral sheet) ( Figure 1).…”

“…It is important to underline that this method does not require the knowledge of solar wind parameters for selecting each type of solar events (quiet or each type of disturbed events). This is in view of the fact that this method has been developing before having all solar wind parameters through satellites data (year 1989) and has been validated by Ouattara and Amory Mazaudier (2009). Therefore, pixel diagram appears as a good tool because its gives an excellent result during the evaluation of geomagnetic storms effects on ionosphere (e.g.…”

One-Day-Shock, Two-Days-Shock and Three-Days-Shocks foF2 Diurnal Variation with Solar Cycle Phases at Ouagadougou Station from 1966 to 1998. Comparison with IRI 2012 Predictions

“…To exhibit the all geomagnetic activities and particularly that of shock, the pixel diagram (see Figure 1: for more details about the description and the used of this diagram see (Ouattara & Amory Mazaudier, 2009) and the references therein) is a good tool. The used of the pixel diagrams allows (Gyébré et al, 2018) to classify each shock activity into three types (1) one-day-shock [its action time duration on the ionosphere does not exceed one day], (2) two-days-shock [its action time duration on the ionosphere is more than one day and does not exceed two days] and three-days-shock [its action time duration on the ionosphere is more than two days and does not exceed three days] (see figure 2 below).…”