Estimating Storm‐Time Maximum Fluxes of Outer Radiation Belt Electrons: Combining Van Allen Probes and GPS Satellite Observations

Abstract By combining 6‐year Van Allen Probes data and 19‐year US Global Positioning System (GPS) satellite NS41 observations, covering the maximum and declining phases of both Solar Cycles 23 and 24, we comprehensively investigate the statistical distributions of the storm‐time maximum fluxes ( j max ) of outer belt electrons and their critical controlling geomagnetic and solar wind conditions. We find that electron fluxes with energies ∼0.5–2 MeV at L = 4.2–4.5 are closely modulated by the time‐integrated AL index (Int(AL)), having strong correlation coefficients (CC > 0.7) between 6‐hr averaged electron fluxes and Int(AL) calculated with a sliding time window. The consistent observations of j max from Radiation Belt Storm Probes and NS41 confirm the controlling influence of continuous substorms as measured by Int(AL) on producing j max , showing strong and linear correlation between them in logarithmic space, even when applied to storms with (SYM‐H) min < −300 nT. Meanwhile, the combination of low solar wind pressure, large and sustained substorms and solar wind electric field are important predictors for efficient electron acceleration.