Ejecta model development at pRad (u)

In July 2009 we fielded three explosively (HE) driven Richtmyer-Meshkov instability experiments at the LANSCE Proton Radiography Facility (pRad), and in August of 2009 we fielded one flyer plate experiment on the pRad 40 mm powder gun. One HE experiment was done in vacuum, and the other two within four atmospheres of noble gasses: Xe and Ne. These two gases were chosen to study the viscous effects on ejecta formation. It is unexpected, but the viscosity {eta} of Ne is twice that of Xe, and, due to the atomic mass difference between the two, the kinematic viscosity ({eta}/{rho}) of Ne is about ten times that of Xe. The results showed that ejecta formation is sensitively linked to the gas density, which implies that the Weber number is more important in ejecta formation than the Reynolds number.