Hypervelocity impact studies using the 2 MV Van de Graaff accelerator and two-stage light gas gun of the University of Kent at Canterbury

Abstract

The hypervelocity impact facilities of the University of Kent are described. They comprise a 2 MV Van de Graaff accelerator for the electrostatic acceleration of dust particles (mass 10(-19)-10(-13) kg and velocities 0.5-90 km s(-1)) and a two-stage light gas gun firing millimetre-sized particles at 1-5.7 km s(-1). Results for impact ionization studies using iron dust accelerated in the Van de Graaff and hitting a variety of metal targets (gold, silver, indium, iron, rhodium and molybdenum) are presented. Over the range 2-80 km s(-1),the ionization yields are found to be similar to within a factor of 20 at low velocity and converge to within a factor of five at high velocity. The light gas gun is used to investigate the volumes of craters in metal targets for impacts of 1 mm diameter stainless steel spheres on aluminium at velocities in the range 2-5 km s(-1). For normal incidence the crater volume scales with the square of the impact velocity. For oblique impacts at a fixed velocity (5 km s(-1)) it is found that the crater volume scales with the cosine of the impact angle.