Studies of reactive and nonreactive metals–ejecta–transporting nonreactive and reactive gases and vacuum

Abstract

We report recent results of reactive and nonreactive metal fragments–ejecta–transporting in vacuum, and reactive and nonreactive gases. We postulate that reactive ejecta transporting in a reactive gas, such as D2, will rapidly break up into smaller fragments in situations where they are otherwise hydrodynamically stable in a nonreactive gas such as He. The ejecta were formed through explosive loading of thin Sn (nonreactive) and Ce (reactive) coupons that included machined periodic perturbations on their backsides, which interfaced with vacuum, He or D2. Coupon surface hydrodynamics, ejecta mass- and size-velocity distributions, and ejecta temperatures were diagnosed with laser doppler velocimetry, piezoelectric transducers, Mie scattering and infrared imaging (IR). In addition, particle imaging velocimetry was applied for the first time to evaluate ejecta transport to study ejecta sheet breakup dynamics. The IR data demonstrate that rapid reactions of Ce ejecta transporting in D2 occur.