Dielectric Charging of Polyetheretherketone Insulation Used in Spacecraft Superimposed DC Voltage

Spacecraft charging of dielectrics superimposed dc voltage is a key issue in insulation that exposed in the space environment. In this paper, charge deposition, transport, accumulation of polyetheretherketone (PEEK) dielectric were studied under electron irradiation (0.3 MeV and 5×10^-7 A/m²). The effects of operating voltage on the charging process were considered. A 2D finite element simulation model was conducted for modeling the charging in a plate sample structure. The operating voltage ranges from -5 kV to +5 kV. Charge transport process considering the energy deposition of the irradiated electrons, the radiation-induced conduction, and the charge injection was employed in the modeling. The calculation results indicate that the charging results of PEEK material present a rapid charging rate by the electron beam. Positive voltages can decrease the surface potential, while it has little influence on the space charge and the electric field inside the sample. For example, the maximum electric field difference between ±5 kV operating voltages is 2.06 kV/m, but the surface potential difference is 10152V. It can be concluded that a high surface potential with a rapid charging rate occurs in the PEEK material under the electron beam superimposed the dc voltage. The applied voltage affects the electron energy so as to the change of dielectric charging processes.