  Ion thruster is a revolution technology with potential applications in space
mission but the thrusters operation lifetime is limited by the sputtering from
thruster components. In this work, molecular dynamic simulations are performed
to explore the dependence of deformation characteristics of an aluminum surface
on incident angle and kinetic energy under low-energy xenon-ion impact. The
fraction of non-12-coordinated atoms is used to quantitatively characterize the
microstructural evolution and defect density levels. It is found that defect
density level has a linear relation with incident energy, and there exists a
critical incident angle around 20 degrees, at which the aluminum surface has
the maximum defect density level. In addition, a collision model is developed
to theoretically reveal the physical mechanisms behind the dependence. Our
findings may helpful in developing long endurance electric propulsion devices
for practical applications.
