The magnetopause electron layer along the distant magnetotail

An energetic electron layer is found immediately adjacent to, and outside of, the magnetopause surface along the distant magnetotail (−40 ≲ X SM ≲ −15 R E ). The layer has been detected using Caltech instrumentation aboard the earth‐orbiting spacecraft IMP‐8 and is observed for electrons with energies E ≳ 200 keV. The present study shows that such electrons form a layer ∼ 3 R E thick and are strongly streaming in a well‐ordered pattern, especially along the dusk magnetopause. The energy dissipation implied by the persistent flow may be a direct indication of nearly continuous magnetic merging at or near the magnetopause.