Study of the effects of SiC filler on the internal charging of LDPE in space environment

• We examine the effects of SiC filler on the internal charging of LDPE.
• High field conductivity is considered in the calculation of the electric field.
• Increasing SiC filler concentration will decrease the electric field of dielectric.
• Particulate size of SiC is of substantial effect on the electric field.
• β-form SiC is of conductive ability superior to α-form SiC.

The systematic investigation on the effects of the parameters of SiC filler on the internal charging of low density polyethylene (LDPE) has been performed. The injected current density and the absorbed dose rate in LDPE are calculated by means of the Monte Carlo method based on Geant4 code. Using these obtained quantities and taking into account the high-field conductivity, the electric field distributions in the LDPEs with SiC fillers of the different parameters have been calculated. The following significant results are given. With the increase of SiC filler concentration, the obvious increase of the electric field appears at increasingly small depth in LDPE. At lower SiC filler concentrations, large incident current density leads to large electric field magnitude Emax, but at higher SiC filler concentrations, Emax values under different incident current densities become close to each other. In addition, large particulate size of SiC has a substantial effect on the electric field distributions at high SiC filler concentrations, the contribution of black SiC to the decrease in the electric field is superior to that of green SiC, and the addition of β-form SiC leads to significant low Emax, compared to that by adding α-form SiC.