Intense Energetic Electron Precipitation Caused by the Self-Limiting of Space Radiation

Understanding intense electron precipitation is crucial for characterizing radiation belt loss and assessing related impacts on the atmosphere. We investigate the evolution of electron flux during an ensemble of 70 geomagnetic storms, focusing on equatorial and low-Earth orbit observations of trapped and precipitating similar to 30-100 keV energy electrons. We reveal that the most intense electron precipitation is associated with equatorial flux capping through self-limiting processes, for example, as described theoretically by Kennel and Petschek (1966, ). Our results indicate that the most intense electron precipitation is caused by electron injections associated with self-limiting processes. Dawn side injections are observed to have fluxes that exceed the Kennel-Petschek limit, consistent with the excitation of strong chorus waves and resulting in intense precipitation and return of the trapped flux to the Kennel-Petschek limit. Our results clearly demonstrate the important role of self-limiting processes in affecting the dynamics of newly injected electrons and driving intense electron precipitation. In this study, we investigate the behavior of electrons in Earth's magnetosphere and how they impact the upper atmosphere during geomagnetic storms. We focus on electron precipitation events with energies that are often associated with pulsating aurora. Our findings show that during the most intense periods of electron precipitation, the electron flux in the equatorial region is associated with a natural process that caps it at an upper limit. We also reveal that electron injections occurring on the dawn side of the magnetosphere trigger these processes, leading to the most significant electron precipitation events occurring in this region. Our results highlight the importance of these natural self-limiting processes in shaping the behavior of the radiation belts, and the potential impact of the related precipitation of these particles into the upper atmosphere. Understanding these processes is crucial for studying space weather and its potential effects on our planet's atmosphere and climate. We investigate the evolution of electron flux and pitch angle distributions (PADs) during intense precipitation eventsLow Earth orbit PADs show strong pitch angle diffusion associated with intense precipitation at dawn side magnetic local timesBoth are associated with eventual flux capping at the Kennel-Petschek limit after electron injections