[P-EM15] Dynamics of Magnetosphere and Ionosphere

[PEM15-02] The Key Role of Magnetic Curvature Scattering in Energetic Electron Precipitation During Substorms

★Invited Papers

*Ying Zou¹, Xiaojia Zhang^2,3, Anton V Artemyev³, Yangyang Shen³, Vassilis Angelopoulos³ (1.Johns Hopkins University Applied Physics Laboratory, 2.University of Texas at Dallas, 3.University of California, Los Angeles)

Keywords:Energetic electron precipitation, Whistler wave, Field line curvature scattering, Conductance

Energetic electron precipitation (EEP) significantly affects ionospheric chemistry and lower ionosphere (<100 km) conductance. Two mechanisms have been proposed to explain what causes EEP: whistler-mode wave scattering, which dominates at low latitudes (mapping to the inner magnetosphere), and magnetic field line curvature scattering, which dominates poleward. In this case study, we analyzed a substorm event demonstrating the dominance of curvature scattering. Using ELFIN, POES, and THEMIS observations, we show that 50-1,000 keV EEP was driven by curvature scattering, initiated by an intensification and subsequent earthward motion of the magnetotail current sheet. Using a combination of Swarm, total electron content, and ELFIN measurements, we directly show the location of EEP with energies up to about 1 MeV, which extended from the plasmapause to the near Earth plasma sheet. The impact of this strong substorm EEP on ionospheric ionization is also estimated.