Title: Molecular Dynamics Simulations of Radiation Damage in Amorphous Silica: Effects of Hyperthermal Atomic Oxygen

Presenter: Vanessa Oklejas

Affiliation: The Aerospace Corporation

Abstract: In low-earth orbit (LEO), the external surfaces of a spacecraft typically experience exposure to hyperthermal atomic oxygen (AO) with a flux of 1015 O atoms cm-2 s-1. At this energy, AO initiates a number of chemical reactions and physical changes within materials such as oxidation,crazing or color changes. To study the effects of materials damage due to hyperthermal AO, molecular dynamics (MD) was used to simulate the collision of AO with amorphous silica. The results of MD simulations of collisions between AO (at varying kinetic energies) and the substrate material will be presented. Specifically, the penetration depth of the projectile AO atom, the amount and location of displacement damage, as well as changes in chemical and molecular properties will be used to gain mechanistic insight into radiation-induced damage to material that has been experimentally observed.