Measurements and Modeling of Electron Precipitation Induced by the Ionospheric Heating Experiment

Abstract Through the emission of high‐frequency radio waves, ground‐based heating facilities can generate Extremely‐Low‐Frequency (ELF) and Very‐Low‐Frequency (VLF) waves in the ionosphere, a portion of which can penetrate into the Earth's radiation belts and influence the electron population therein. Although various measurements of ELF/VLF waves generated by ionospheric heating experiments have been reported, combined analysis using both observations and simulations remain quite limited and, thus, the underlying effects of these experiments are not well understood. In this study, we quantify these effects using measurements of plasma waves and high‐energy electrons during the joint experiment conducted between the China Seismo‐Electromagnetic Satellite (CSES) and the ionospheric heater SURA on 17 November 2021. We show that SURA‐generated ELF/VLF waves are mostly in the frequency range of 1–5 kHz as measured by CSES, with an amplitude of ∼50 pT at 0.8–2 kHz. The overall structure is similar to previous measurements of ELF/VLF waves generated by the High‐Frequency Active Auroral Research Program (HAARP). These waves can, in principle, influence electrons in the 100–250 keV energy range, mostly via pitch‐angle diffusion. On basis of further simulations of the evolution of electron phase space density under the impact of SURA‐generated ELF/VLF waves, our modeling output shows favorable consistency with the electron flux variations measured by CSES. Our results support a causative relation between the SURA heating experiment and the CSES‐observed dynamics of ELF/VLF waves and energetic electrons, which has important implications to further our understanding of the near‐Earth space environment and to develop artificial radiation belt remediation techniques.