“…In the Earth's outer radiation belt, the great variability of low‐energy (∼10–300 keV) electron injections and betatron acceleration during dipolarization events (Birn et al., 1998 , 2012 , 2014 ; Gkioulidou et al., 2015 ; Liu et al., 2016 ; Runov et al., 2015 ; Su et al., 2014 ; Tang et al., 2022 ; Turner et al., 2015 , 2016 ), and of the plasma and geomagnetic field conditions determining their subsequent acceleration to higher energy (O. V. Agapitov et al., 2019 ; Birn et al., 1997 ; Horne et al., 2005 ; Summers et al., 1998 ), are important obstacles to reliable predictions of full relativistic electron flux energy spectra during highly disturbed periods.…”