Abstract Recently, Hua et al. (2026, https://doi.org/10.1029/2025GL120881 ) combined observations during a 4‐day storm period with numerical simulations and concluded that the abrupt electron loss in the field‐line‐curvature scattering (FLCS) region played a leading role in shaping the outer boundary of radiation belt (RB); the authors conjectured that the simple yet fundamental FLCS process, neglected in previous global radiation belt models, is sufficient to explain the dynamics of the outer electron belt boundary. In this commentary, we discuss the importance of the FLCS‐induced loss mechanism in the light of (a) existing information about the energetic electron precipitation and (b) contradictory conclusions of another recent study (Huang et al., 2025, https://doi.org/10.1029/2025ja033965 ). While in a qualitative sense we agree with the conjecture by Hua et al. (2026, https://doi.org/10.1029/2025GL120881 ) accurate quantification of the FLCS effects, based on a more realistic field model is still needed. Possible pathways for solving this challenging problem are outlined.
Сергеев et al. (Fri,) studied this question.