Low-altitude observations of whistler-driven precipitations from plasma sheet

Earth’s magnetotail is characterized by stretched magnetic field lines, which is a favorable condition for magnetic field line curvature scattering (FLCS) of energetic electrons. Low-altitude observations usually detect isotropic electron precipitations from the magnetotail, without tell-tale signatures of wave-driven precipitations. However, meso-scale transient dipolarization within fast plasma flows may locally suppress the field-aligned curvature scattering, clearing a path for electron precipitations due to wave-particle resonant interactions. In this presentation, we analyze low-altitude ELFIN observations of whistler-driven precipitations from the magnetotail, in particular their typical energy range and spatial characteristics. Such ELFIN observations are supported by in-situ observations of magnetic field dipolarization and whistler-mode waves by near-equatorial THEMIS spacecraft. We also discuss if such joint ELFIN/THEMIS measurements of whistler-mode wave activity and associated precipitations may be used for magnetic field line mapping during plasma sheet injections.