Nowcast model for low‐energy electrons in the inner magnetosphere

Abstract

AbstractWe present the nowcast model for low‐energy (<200 keV) electrons in the inner magnetosphere, which is the version of the Inner Magnetosphere Particle Transport and Acceleration Model (IMPTAM) for electrons. Low‐energy electron fluxes are very important to specify when hazardous satellite surface‐charging phenomena are considered. The presented model provides the low‐energy electron flux at all L shells and at all satellite orbits, when necessary. The model is driven by the real‐time solar wind and interplanetary magnetic field (IMF) parameters with 1 h time shift for propagation to the Earth's magnetopause and by the real time Dst index. Real‐time geostationary GOES 13 or GOES 15 (whenever each is available) data on electron fluxes in three energies, such as 40 keV, 75 keV, and 150 keV, are used for comparison and validation of IMPTAM running online. On average, the model provides quite reasonable agreement with the data; the basic level of the observed fluxes is reproduced. The best agreement between the modeled and the observed fluxes are found for <100 keV electrons. At the same time, not all the peaks and dropouts in the observed electron fluxes are reproduced. For 150 keV electrons, the modeled fluxes are often smaller than the observed ones by an order of magnitude. The normalized root‐mean‐square deviation is found to range from 0.015 to 0.0324. Though these metrics are buoyed by large standard deviations, owing to the dynamic nature of the fluxes, they demonstrate that IMPTAM, on average, predicts the observed fluxes satisfactorily. The computed binary event tables for predicting high flux values within each 1 h window reveal reasonable hit rates being 0.660–0.318 for flux thresholds of 5 ·104–2 ·105 cm−2 s−1 sr−1 keV−1 for 40 keV electrons, 0.739–0.367 for flux thresholds of 3 ·104–1 ·105 cm−2 s−1 sr−1 keV−1 for 75 keV electrons, and 0.485–0.438 for flux thresholds of 3 ·103–3.5 ·103 cm−2 s−1 sr−1 keV−1 for 150 keV electrons but rather small Heidke Skill Scores (0.17 and below). This is the first attempt to model low‐energy electrons in real time at 10 min resolution. The output of this model can serve as an input of electron seed population for real‐time higher‐energy radiation belt modeling.