Spacecraft charging in the supra-auroral region

Electrostatic charging of spacecraft in electrostatic shock acceleration regions above the auroras is predicted to occur. Electrostatic shocks are thought to produce the electron streams that generate auroras. These electron streams can charge spacecraft to high potentials in the altitude range from 3000 to 8000 km in the auroral region. Ion beams accelerated upward in electrostatic shocks contribute to charging as well. It is shown that the potential can be at most the maximum potential across the shock. Charging is altitude-dependent within a shock