Direct observation of large shock impedance jump upon shock-induced densification of powdered materials confirmed by in situ shock pressure and particle velocity measurements

Shock pressure and particle velocity measurements have been performed separately on a powdered material under a similar shock loading condition by employing time-resolved luminescence spectroscopy and velocity interferometry (VISAR). Shock pressure measurement adopts the pressure-shift characteristic of ruby crystal that is used as a window material. Exactly the same shock condition could be realized for the particle velocity measurement by using a sapphire crystal as a window. A good agreement between the results of two different measurements has been obtained and they indicate a 7 times or more increase in shock impedance of the powdered material.