On the Energy-Dependent Deep (L less than 3) Penetrations of Energetic Electrons (10s of keV to multi-MeV)

Energetic electrons of 100s of keV (1000 electric volts) to MeV (million electric volts) in the space environment have detrimental effects on spacecraft subsystems and are hazardous to astronauts during their extravehicular activity. These energetic electrons are trapped by the Earth's magnetic field, normally existing in two zones, referred to as the inner belt (within one Earth Radii from the surface of the equator) and outer belt (between 2-6 Earth Radii from the surface of the equator). Their source, loss, and variations have been a long-standing research topic. The discovery (supported by an NSF grant) of Cosmic Ray Albedo Neutron Decay (CRAND) produced electrons being the primary source of electrons near the inner edge of the inner belt has changed much of the conventional understanding of inner belt electron dynamics. The current project is to conduct a broader investigation of the dynamics of the inner belt electrons and to train and educate graduate and undergraduate students from diverse backgrounds in the next-generation Science, Technology, Engineering, and Mathematics (STEM) workforce. The research results will also enhance the current prediction ability of the variation of the inner radiation belt electrons, which has its own practical space weather application for spacecraft design and operation. Thus, the project will broadly impact education, societal applications, and its intrinsic science investigation.

This project investigates the inward transport of energetic electrons from the outer electron belt and their energy dependence on how deep they can penetrate given a geomagnetic storm event. Recent observations show that 10s-100s of keV electrons are frequently seen in the slot region (2