Slow electron phase space holes: Magnetotail observations

Abstract

We report multispacecraft observations of slow electrostatic solitary waves in the plasma sheet boundary layer. The electrostatic solitary waves are embedded in a region with field-aligned electron flows and are interpreted as electron phase space holes. We make unambiguous velocity and length estimates of the electron holes, v_EH∼500 km/s and l_||∼2-4λ_De, where l_|| is the parallel half width. We do not detect any magnetic signature of the holes. The electrostatic potentials of the holes are of the order eϕ/k_BT_e∼10%, indicating that they can affect electron motion and further couple the electron and ion dynamics.