Multisatellite Observations of Ion Holes in the Earth's Plasma Sheet

We present the first observations of electrostatic solitary waves with potential negative polarity around a fast plasma flow in Earth's sheet. The are observed aboard four Magnetospheric Multiscale spacecraft, which allowed accurately estimating wave properties. Based on data set 153 waves, we show that they locally one-dimensional Debye-scale structures amplitudes up to 20% local electron temperature and propagate at frame speeds ranging from tenth few ion-acoustic arbitrary angles magnetic field. associated multi-component proton distributions their velocities those beam-like population. argue ion holes, nonlinear produced by ion-streaming instabilities, conclude once ions not magnetized, holes can oblique