Parametrization of Energetic Ion and Electron Fluxes in the Near‐Earth Magnetotail

• Published in: Journal of geophysical research. Space physics Vol. 128; no. 9
• Main Authors: Gao, Luphi, Vainchtein, Dmitri, Artemyev, Anton, Gabrielse, Christine, Runov, Andrei, Kellerman, Adam
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-09-2023
• Subjects: Auroral electrojet; Auroral electrojets; Auroral kilometric radiation; Boundary conditions; Earth; Electrojets; Electron energy; Electron flux; Electrons; energetic particles; Geomagnetic activity; Geomagnetic tail; GOES satellites; Ions; Jupiter; Magnetic field configurations; Magnetic fields; Magnetospheres; Magnetotails; near‐Earth plasma sheet; Parameterization; Perturbation; Plasma; plasma injections; Radiation; Radiation belts; Ring current models; Ring currents
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2023JA031425

The near‐Earth plasma sheet region is the main source of energetic (tens to hundreds keV) ion and electron populations transported by convection and injections into the inner magnetosphere. Energetic ions from the plasma sheet contribute to the ring current, whereas energetic electrons contribute to the radiation belt seed population for further acceleration to relativistic energies. Near‐Earth plasma sheet energetic fluxes have been traditionally used to set boundary conditions for radiation belt and ring current models. This study provides an empirical parametrization for ∼75 keV flux intensity as a function of the geomagnetic activity index auroral electrojet and the equatorial magnetic field Bz. Such parametrization includes the dynamic magnetic field configuration in the near‐Earth plasma sheet and may be merged with empirical magnetic field models. We also provide models extending this parametrization to the [20, 300] keV of electron energy range and [75, 300] keV of ion energy range. The parametrization is developed based on THEMIS and Geostationary Operational Environmental Satellite measurements, and verified by comparison with MMS measurements in the near‐Earth plasma sheet. This parametrization incorporates meso‐scale transient flux variations associated with Bz perturbations into ring current and radiation belt simulations.
Key Points
A new model of energetic electron and ion fluxes in the near‐Earth plasma sheet has been developed
The model is based on flux parametrization by equatorial magnetic field magnitude and auroral electrojet index
Energy ranges for model validity have been investigated