Abstract

The Hopkins Extreme Materials Institute (HEMI) recently installed a hypervelocity impact facility (HyFIRE) including a two-stage light gas gun at Johns Hopkins University in Baltimore, MD. The HyFIRE launcher has a launch tube bore diameter of 7.62 mm and is designed to attain launch velocities up to 7 km/s. The enclosed ballistic range and terminal test chamber provide multiple axes with which to view both projectile free flight and terminal impact, maximizing diagnostic access to events of interest.

Initial test diagnostics include ultra-high-speed optical video and orthogonal 300 kV flash x-ray imaging. Photon doppler velocimetry for surface velocity measurement—currently used in HEMI’s laser shock facility—as well as emission spectroscopy/pyrometry are planned, providing researchers across multiple disciplines with the ability to investigate the coupling of mechanics, physics and chemistry present in high energy density impact events. Initial experiments at the facility investigate the fragmentation of inert impactors on anvil targets, with an aim towards identifying the dominant mechanisms controlling the fragmentation characteristics, temperature distributions and trajectories of generated debris fields.

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