A high‐resolution, particle‐velocity gauge system was developed to obtain a hydrodynamic streamline in the flow field associated with shock waves or detonation products. The system is composed of a passive current loop (stirrup probe) embedded in the host material, a magnetic field generator to establish a Lorentz force, and a computer‐controlled, analog‐to‐digital transient recorder to monitor the gauge response. The operation principle is that the motion of one side of a rectangular loop in a magnetic field produces a current proportional to the velocity of that leg. System tests were conducted with 50‐mm diam. by 50‐mm long cylinders of 1,3,5‐triamino–2,4,6‐trinitrobenzene (TATB) explosive and explosive‐driven polytetrafluoroethylene (PTFE). The velocity profiles obtained have a time resolution of a few nanoseconds with an amplitude uncertainty of approximately 2% based on a system error analysis. Detailed descriptions of the gauge system components are included.