Spectral measurements of hypervelocity impact flash

We have revisited the well-known phenomena of impact flash by examining the optical spectra generated by hypervelocity impacts at velocities up to several tens of kilometers per second. This particular effort, sponsored by an LDRD from our laboratories, has looked at the flash from impacts over a range of velocities from 6 to 25 km/s, using two different experimental environments. Both two- and three-stage light-gas guns and magnetically driven flyers on the Z accelerator were used. Here, we describe the latter set of experiments. Using standard tabulations of atomic spectral data, we were able to identify strong spectral lines from the principal materials used in the various shots. We demonstrated that the impact-flash spectra were qualitatively reproducible from shot to shot, and have confirmed the feasibility and credibility of using impact-flash spectroscopy for remote sensing applications such as meteoroid-impact or missile-defense engagement analyses.