The insulating material flashover induced by an electrostatic electromagnetic pulse radiation field in a complex electromagnetic environment is a big concern in spacecraft surface materials. Polytetrafluoroethylene (PTFE) is the most often used insulation material in spacecraft. For this reason, the secondary electron emission avalanche (SEEA) model is proposed for the theoretical analyses of and experiments on the PTFE surface flashover induced by an electrostatic electromagnetic pulse radiation field. We use the current probe sensor to measure the induced flashover current waveform on the grounding wire and combine the probability of the electrostatic electromagnetic-pulse-induced flashover under different electrode voltages and electrostatic discharge (ESD) simulator output voltages. First, the SEEA theory is established considering the flashover voltage without an external electrostatic electromagnetic pulse field. The flashover voltage is then applied to the needle-plate electrode, and the distorted electric field is formed at three nodes of electrode-PTFE-air. Second, the flashover voltage with an external electrostatic electromagnetic pulse field is taken into account. The external field producing horizontal and vertical electric field components between the electrodes is fully investigated. Third, experimental results on the electrostatic electromagnetic-pulse-induced PTFE surface flashover using a needle-plate electrode structure are analyzed and discussed in detail. All findings are supported by the proposed SEEA model in an electrostatic protection using PTFE material.

Purpose The purpose of this paper is to research the induced flashover laws of different insulation materials under electrostatic electromagnetic pulse, and the induced flashover characteristics of different electrode structures are further explored. Design/methodology/approach According to standard IEC 61000–4-2, an experimental system of electrostatic electromagnetic pulse flashover for insulation materials is established. The induction flashover laws of polytetrafluoroethylene, epoxy resin and polymethyl methacrylate surface-mounted finger electrodes under the different intensity of electrostatic electromagnetic pulse are researched. The influence of the finger electrode, needle–needle electrode and needle–plate electrode on insulation flashover was compared. Secondary electron emission avalanche (SEEA) and field superposition theory are used to analyze the experimental results of electrostatic electromagnetic pulse induced flashover. Findings The larger the dielectric strength of insulation materials, the more difficult flashover occurs on the surface. The field superposition enhances collision ionization between electrons and gas molecules, which leads to the insulation materials surface induced flashover easily by electrostatic electromagnetic pulse. The sharper the electrode shapes on the insulation materials surface, the stronger the electric field intensity at the cathode triple junction, more initial electrons are excited to form the discharge channel, which easily leads to flashover on the surface of the insulating material. Originality/value The proposed field superposition combined with the SEEA method provides a new study perspective and enables a more rational, comprehensive analysis of electrostatic electromagnetic pulse induced flashover of insulation materials. The work of this paper can provide a reference for the safety protection of spacecraft in orbit under a strong electromagnetic field environment, increase the service life of spacecraft and improve the reliability of spacecraft’s safe operation in orbit. It provides a basis for the selection of insulation materials for equipment under the different intensities of the external electromagnetic environment.