Results

Q1: What is the missing loss mechanism of ring current electrons besides the diffusive scattering by whistler-mode waves?

Results:

✔ Two potential mechanisms were considered and ruled out: scattering by ECH waves and TDS

✔ Additional potential candidate mechanisms were identified: sporadic high-amplitude chorus waves, KAW, nonlinear effects, cold plasma density variations, hiss and exohiss

Future recommendations:

➤ Independent validation using LEO observations

➤ Verification based on the ratio between trapped and precipitating particles

➤ Coordinated conjunctions with multiple satellites, including NASA’s Van Allen Probes, JAXA’s Arase, ESA’s PROBA-3, and NOAA’s POES and DMSP

➤ Enhanced modeling, including density-dependent effects

Q2: What is the energy of electrons that are significantly influenced by EMIC waves? A related question is why is the EMIC wave activity in the magnetosphere not always accompanied by the energetic particle precipitation at the conjugate point on LEO orbit?

Results:

✔ EMIC waves drive electron PSD minima at multi-MeV energies, but not at seed energies

✔ Evidence from LEO indicates EMIC-driven precipitation of electrons at 100s of keV and above

✔ Low-energy electron scattering may occur through non-diffusive scattering

✔ Statistical distributions of EMIC waves have been compared across multiple satellite missions

Future recommendations:

➤ Refine EMIC wave datasets. Intercalibrate and combine then into a global dataset spanning multiple observations and solar cycles

➤ Develop new EMIC wave models including frequency spectra, ion composition, and plasma environment

➤ Incorporate nonlinear and non-diffusive effects into modeling and interpretation

Q3: Which energy range of precipitating electrons has the largest impact on the chemistry and dynamics of the middle atmosphere?

Results:

✔ Particle precipitation was reviewed using observations from multiple satellites

✔ Particle precipitation from the inner magnetosphere (including radiation belts and ring current) was shown to significantly affect mesospheric ozone, NO, and N₂O density variations

✔ The May 2024 geomagnetic storm was analyzed in detail as a challenge event

Future recommendations:

➤ Obtain realistic ionization rates based on observed and modeled spectra of precipitation particles (keV to multi-MeV)

➤ Develop a global reference map of ozone, NO, and N₂O, accounting for seasonal and latitudinal variations and excluding phenomena such as stratospheric warming

➤ Explore community models (e.g., via CCMC) and establish coupling between inner magnetosphere and atmosphere models