Polyimide and FEP charging behavior under multienergetic electron-beam irradiation: Experiments and a simple model

This RIC model has been built following ideas developed by Gross [6], and applying them to model a surface potential experiment. The main drawback of this model, in our opinion, is that a single trapping level has been considered. The assumption that the charge centroid displacement can be neglected is also questionable. This model has to be developed. It has however to be underlined that, for historical and practical reasons, the models of the insulators in current use to calculate spacecraft charging are commonly based on more primitive (and mostly erroneous) assumptions, as a field depending conductivity. Understanding the conduction mechanisms and reducing the charging levels are important industrial issues for satellite designers and manufacturers, but more attention may have been devoted these last years to understanding the plasma features and variations, than on modeling the material. Models of the insulator are thus few and oversimplified. Our purpose is to improve them, and to revivify the ancient link between electret and space researchers (once personified by Bernhard Gross), which might be useful for both communities.