## 2 Methods and Data
### Case Selection Criteria for FEE and Solar Wind Coupling Analysis  
The volume of the FEE catalog is estimated in thousands of the equatorial flux enhancements. In the case of daily multiple \(>\) 30 keV FEE enhancements, some of them (except the very first one) may be a consequence of the eastward drift of electrons that had previously ended up in the forbidden zone somewhere to the west. These processes can be separated by considering electrons of different energy that drift at different speeds. The drift period \(Td\) (in hours) takes into account the relativistic correction as determined by the expression [18]:  
\[Td=\frac{736}{\gamma\cdot LE}, \tag{3}\]  
where \(E\) is the kinetic energy in keV, \(L\) is the drift shell in Earth's radii, \(\gamma\) is the relativistic correction equal to \((E+mc^{2})/mc^{2}\), \(m\) is the rest mass, and \(c\) is the speed of light. Figure 2 shows the dependence of \(Td\) on \(E\) for different \(L\) from 1.05 to 1.2. As one can see, drift periods for 30, 100 and 300 keV energies are very different at low L-shells. Therefore, the lack of simultaneous enhancements in low and high energy channels can be explained by drift motion at different velocities. Namely at L = 1.2, the 300-keV electrons drift azimuthally with the rate of 4\({}^{\circ}\) per minute and, thus, quickly escape from the injection region, in contrast to the 30 keV electrons. Hence, it is hard to observe the simultaneous injection of 30 keV and 300 keV electrons.  
Each event is a rather complex combination of particles and satellites moving in opposite directions in longitude. We suppose that the time of simultaneous enhancements in 30 keV and 100 keV channels may be very close to the \"injection moment\" and hence can be used in further analysis. If the satellite does not observe higher energy electrons, this means that these electrons have already escaped from the injection region, and the low-energy electrons continue to drift slowly and are observed by satellites. This means that the time we are interested in has passed at least an hour or more prior.  
Figure 1: (**Top**) Examples of 30 min time profiles of FEE enhancements in energy channels \(>\) 30\(>\)300 keV on 31 March 2001 and 9 November 2004. Units of particle flux intensity (pfu) is particles per (cm\({}^{2}\) s sr). (**Bottom**) Fluxes of \(>\)30 keV electrons measured by FOES-16 at 8—16 UT on 31 March 2001 and by FOES-15 at 16-24 UT on 9 November 2004 in geographic coordinates.  
Considering the above, the first observed enhancement per day is of greatest interest. However, flux enhancements in the 30 keV FEE may last for several consecutive days. Some of them may be related directly to the injection, while others are a consequence of a slow azimuthal drift of low-energy electrons. Therefore, we considered only the first enhancement in such a long-duration event.  
Thus, the observation time can be used to search for the solar wind disturbance resulting in electron flux enhancements deeply inside the magnetosphere, or rather in the topside ionosphere. We selected several \"first\" FEE enhancements in \(>\)30 keV and 100/300 keV from the catalog that were observed during the great geomagnetic storms with the SYM-H index reaching values of \(-\)400 to \(-\)500 nT in the 23 rd and 25 th solar cycles. The storms belong to the class of super storms according to criterion suggested in (e.g., [45; 46; 47]).