A mechanism of deep dielectric charging and discharging on space vehicles

Summary form only given, as follows. Motivated by the recent sudden loss of AT&T Telstar 401 satellite occurring after a huge solar coronal mass ejection event, we propose a mechanism of bulk charging build up and subsequent discharging on spacecraft. Very energetic plasma events in the Earth´s space are often caused by solar coronal mass ejections. Catastrophies of spacecraft are often associated with such events. The idea proposed in this paper is basic and generic. Since high energy (MeV) electrons and ions, bombarding a dielectric surface, penetrate to different depths into the dielectric, a double layer may form inside the dielectric. The very low densities of high energy space plasmas render the layer formation a slow process. Since the ambient electron flux is usually orders of magnitude larger than that of ions, the electron layer is likely built up first and the ion layer much later, perhaps hours or days. The slow ion layer build up may continue well after the passage of an energetic storm. Paradoxically, a follow up period of higher density lower energy (keV) fluxes after the passage would favor an ion layer build up. The double layer formation increases the potential of a disastrous discharge. Also paradoxically, a follow up period of low spacecraft charging level after the passage of a highly energetic storm would also enhance the potential of a discharge, because the potential difference between the electron layer in a dielectric slab and the spacecraft ground would have increased.