[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)

キーワード：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.