Thin sheets of energetic electrons upstream from the Earth's bow shock

ISEE spacecraft observations show that energetic, ≥ 16 keV electrons are injected into the region upstream from the Earth’s bow shock in a thin sheet which lies just behind the sheet of interplanetary magnetic field lines that are tangent to the shock surface. Lower energy electrons leave the shock over a much broader region. Although the energetic electron intensity varies, the sheet is nearly always present and may be a quasi‐steady state feature of the bow shock. The electron velocity distribution in the thin sheet is strongly peaked and is responsible for excitation of electron plasma waves.