Velocity interferometer system for any reflector

Profile of a shockwave going through a solid, Adapted from Marc Meyers's "Dynamic Behavior of Materials"

Velocity interferometer system for any reflector (VISAR) is a time-resolved velocity measurement tool using laser interferometry used to measure the surface velocity of solids moving at high velocities. For solids experiencing high velocity impact or explosive conditions, VISAR plots the free-surface velocity against time to view the shock wave profile of a material (See Figure). VISAR is a useful tool in determining the pressure-density relationship of a material known as the Rankine-Hugoniot conditions or simply the "Hugoniot". In recent years another time-resolved velocity measurement tool called laser Doppler velocimetry has achieved popularity in the shock physics community as an adjunct or replacement for VISAR.

Further reading

• Meyers, Marc André (1994). Dynamic behavior of materials ([Online-Ausg.]. ed.). New York [u.a.]: Wiley. ISBN 978-0471582625.
• Foundations of VISAR