Evidence of Sub‐MeV EMIC‐Driven Trapped Electron Flux Dropouts From GPS Observations

For many years, it was believed that resonant interactions between electromagnetic ion cyclotron (EMIC) waves and radiation belt electrons were restricted to electron energies >1–2 MeV. In recent however, a growing body of experimental evidence has shown EMIC can cause the scattering loss down sub-MeV energies. Using measurements trapped flux from Global Positioning System satellite constellation, we investigate ability significant depletions populations 4 ≤ L* 5. first time, present statistical demonstrating global decreases in response wave activity. Although find losses extend energies, also show strong support for preferentially substantial ultra-relativistic belts.