Collisionless Electrostatic Particle-In-Cell Simulation of Rapid Target Charging Along an Unbiased Surface Due to Hypervelocity Impact Plasmas

Abstract Introduction Hypervelocity impacts (HVIs) refer to conditions at which a small projectile mass, such as a micrometeoroid or dust particle, strikes a target at a velocity exceeding the speed of sound of a material, typically greater than 5 km/s. Both the impactor and the target surface can ablate and ionize due to the high kinetic energy, generating a low-temperature plasma with a large density gradient [1-2]. Rapid target charging (RTC) from HVI plasmas describes the process by which, post-impact, the electrostatic potential of the surface quickly changes. This occurs due to the increased flux of charged particles on the surface during plasma expansion. Phenomena related to this process, including electrostatic discharge (ESD), EMP generation, and possible RF emissions [1,3] provide valuable insight into the mechanisms by which HVIs affect electrical systems of a spacecraft. In contrast to previous experimental and observational analyses related to HVI plasma based RTC [4], this study focuses on a computational analysis of RTC using an electrostatic particle-in-cell model to focus on charge distribution through the immediate dielectric surface of the spacecraft. Our goal is to computationally characterize properties of potential distribution related to RTC (e.g., potential magnitude corresponding electric field values for resulting electrostatic discharges) given initial properties of the system, such as crater geometry and plasma geometry, impactor mass and speed, and surface material selection.