Résumé
CARMEN 3 and CARMEN 4 are two missions developed by the CNES to measure flux particles levels in the radiation belts. These two missions consist in embedding the CNES-developed ICARE-NG instrument on JASON-3 satellite (LEO : 1336 km, 66°) and E7C satellite (GEO with EOR posting) for respectively CARMEN 3 and CARMEN 4. During the CARMEN 4 EOR phase (21.06.2019 to 30.10.2019), E7C run through the same L* spectrum ( L* = 3 - 7) as JASON-3 during the same period. As this two satellites are equiped with the same ICARE-NG instrument but are not at the same altitude, it is relevant to compare the electrons flux temporal evolution measured on both satellites. Common electron energy measured by ICARE-NG during CARMEN 3 and CARMEN 4 missions are 1.6 MeV and 1.8 MeV. Studying temporal electron flux evolution for both missions, guided us to notice for both a remarkable exponential decay of the flux level subsequently to a rapid filling of the outer radiation belt due to an important solar activity (geomagnetic storm). This exponential decay is characterised with a timescale $\tau$ which depends on the mission, the energy, the L* and the concerned exponential decay. These timescales are compared to several previously published estimates. Then, noticing that electrons flux temporal evolution have the same dynamics for both missions, we have been trying to find a projection function from one to the other using classical statistics methods (linear regression, with least squares method). We have found that the correlation between CARMEN 3 and CARMEN 4 data depends on the value of L* Roederer parameter. Indeed, r² correlation coefficient is higher than 0.6 for L* = 3.5 - 4.8 and lesser otherwise. We notice a global same trend of electron flux temporal evolution from both missions. However the correlation is limited by irregularities in the electron flux measured by CARMEN 3. These irregularities causes will be discussed and explained.