Simulation Of Internal Charging Characteristics Of Space Dielectric Materials

With the development of the aerospace industry and the layout of B5G/6G technology,the radiation protection of spacecraft and the stable operation of satellites have become the national strategic needs and the frontier issues of world space science and technology.In recent years,satellite anomalies and fault events caused by the internal charging effect of the dielectric material have become one of the important issues in the field of aerospace radiation protection,which will directly affect the stability and reliability of the spacecraft.In recent years,the Monte Carlo particle transport method has been used in the evaluation of space radiation environmental effects.Compared with the early empirical models used,it can better describe the complex physical mechanism in the particle transport process.It has become a convenient and effective simulation method for internal charging effect.This article uses the open source program toolkit Geant4 to simulate the particle irradiation process,and combines the RIC theoretical model to simulate the one-dimensional internal charging of spacecraft dielectric materials.This thesis discusses some factors,including grounding methods,common space materials and temperature changes,and how they impact the macroscopic electric field changes and microscopic charge transfer processes in space dielectric materials of simple geometric models.At the same time,several space electronic environment models are compared in the internal electric field of polyimide.The research results are as follows:(1)The Geant4-RIC method is feasible to study the internal charging process,and it has been verified that the method can give better prediction results in terms of distribution trend and order of magnitude;(2)In the study of the core-grounded cylindrical dielectric model irradiated by single-energy electron,the irradiated area has an electric field "protruding" distribution which decreases first and then increases under the influence of the radiation conductivity;(3)In the study of the back-ground flat model of different materials(ETFE,PTFE,FR-4,PI and PE)irradiated by single-energy electron,the denser materials(such as ETFE)are more likely to accumulate charges inside,and materials with higher atomic number elements(such as FR4)have stronger charge trapping ability;(4)In the study of the back-ground flat PI model at different temperatures(150-350K)irradiated by single-energy electron,as the temperature decreases,the internal electric field of the material increases significantly.Also,this increase trend slows down at 150K;(5)Based on the existing spatial high-energy electronic environment model,combined with the MC algorithm for any energy spectrum,a high-energy electronic environment model is given,which solves the problem that only single-energy particles can be simulated in previous simulation systems;(6)In the study of the spatial electronic environment energy spectrum on the establishment of the internal electric field of the polyimide,the FLUMIC model and the similar Yan model are more suitable for engineering design due to the redundancy feature,and the AE9 model is more capable of evaluating the actual charging situation of the space dielectric.