Propagation Characteristics Of Electromagnetic Field In Hypervelocity Impact On A Charged Target With A Aperture

The physical process of hypervelocity impact on the charged surface of spacecraft is the change of state of matter under strong dynamic load,which will result in fracture,fragmentation,cratering,cavity formation and expansion of debris cloud.In addition,the impact of space debris on the charged surface of spacecraft will induce the generation of coupled electromagnetic fields.There are inevitably some holes and slots on the surface of spacecraft due to space debris impact,heat dissipation needs and internal and external cable connections.The plasma induced by impact and the resulting electromagnetic field will enter the interior of spacecraft through the holes and slots,which will affect the communication of spacecraft and the normal operation of internal electronic devices.Therefore,the research on the propagation characteristics of electromagnetic field in hypervelocity impact on the charged target plate with holes and slots is helpful to understand the distribution characteristics of electromagnetic field generated after the impact of space debris and the electromagnetic field entering the spacecraft through the holes and slots.It is of great significance to evaluate the safety of spacecraft in orbit and the electromagnetic environment of electronic devices inside the spacecraft.In order to reveal the characteristics of electromagnetic field propagation in hypervelocity impact on the charged target plate with holes and slots,a space vehicle surface simulation test box and supporting charging equipment were designed to simulate the environment with holes and slots and charged.The secondary light gas gun was used as the loading means,supplemented by the plasma diagnosis system,discharge test system,high-speed camera system and electromagnetic field test system The parameters of velocity,incident angle,surface voltage and the distance between the impact point and the hole slot are studied systematically.The main research results are as follows:Plasma is the main factor that affects the discharge and electromagnetic field produced by hypervelocity impact on a charged target with a aperture.The impact velocity directly affects the production of plasma at the target,while the potential of the target affects the number of ionized plasma,and the impact angle affects the contact area between plasma and high and low potential.The number of plasma affects the duration of the discharge process.The contact area between plasma and high and low potential determines the rate of discharge.The duration and rate of discharge directly affect the time and intensity of electromagnetic fieldThe existence of the aperture affects the process of plasma and electromagnetic field entering the chamber through the aperture.The charge concentration caused by the sharp edge of the hole gap will cause the electric field between the hole gap and the low potential behind the target plate.When the plasma conducts the discharge phenomenon between the target plate and the metal mesh,the electric potential difference between the edge of the hole gap and the back of the target plate will also change and produce the electromagnetic field.The eddy field generated by the electromagnetic field in the aperture attracts the plasma into the aperture,and the electromagnetic field will also be hindered by the electric field in the opposite direction in the aperture when it propagates through the apertureThe number of plasma entering the chamber is related to the impact angle,impact position and target potential.60° impact is easier to make the plasma enter the chamber through the aperture,and the closer the impact position is to the hole slot,the more the plasma enters the chamber through the hole slot;the higher the potential of the target plate is,the stronger the vortex field at the aperture is,the more attractive it is to the plasma.The plasma inside the test box has a blocking effect on the propagation of electromagnetic field inside the test box.However,too many plasma inside the test box will lead to the conduction between the high potential target plate and the low potential chamber and the discharge in the chamber.The discharge inside the chamber will lead to the formation of a stronger coupling electromagnetic field inside the chamber.