资源环境科技发展态势分析平台

Shortly after the launch of the Van Allen Probes, a new three-belt configuration of the electron radiation belts was reported. Using data between September 2012 and November 2017, we have identified 30 three-belt events and found that about 18% of geomagnetic storms result in such configuration. Based on the identified events, we evaluated some characteristics of the remnant (intermediate) belt. We determined the energy range of occurrence and found it peaks at E = 5.2MeV. We also determined that the magnetopause location and SYM-H value may play an important role in the outer belt losses that lead to formation and location of the remnant belt. Finally, we calculated the decay rates of the remnant belt for all events and found that their lifetime gets longer as energy increases, ranging from days at E = 1.8MeV up to months at E = 6.3MeV suggesting that remnant belts are extremely persistent.

Plain Language Summary One of the first results reported by the Van Allen Probes mission was the existence of a completely new configuration in which the electron outer radiation belt is split into two belts, resulting in a three-belt structure that has never been reported before. The uniqueness of this event has limited the studies that aim to explain the splitting of the belt, and therefore, the topic is controversial to this date. In this work we show that the occurrence of three-belt events is relatively common and therefore their formation and evolution process can be studied statistically. For the intermediate belt (remnant belt) we found two parameters that may influence their location and formation process. We have also calculated the time that the remnant belt would naturally last in absence of a strong external perturbation and found that the duration increases as the energy of the electrons increases.