Magnetic gauge measurements on the two-stage gun : homogeneous and heterogeneous initiation of high explosives /

One of the reasons for building our gas-driven two-stage gun at Los Alamos was to be able to do shock initiation experiments on high explosives that were too insensitive to initiate with the single-stage gun. In past ARA meetings we have discussed the operation of the gun and the magnetic gauge measurement method. During the past couple of years we have done a number of magnetic gauge experiments on both liquid and solid high explosives. Shock initiation of high explosives depends on the nature of the material - whether it is homogeneous (liquid) or heterogeneous (pressed solid). In the solid explosives, mostly heterogeneous behavior has been measured. In the liquid explosive isopropyl nitrate, classic homogeneous initiation has been measured including the formation of a superdetonation in the shocked liquid. Experiments in both materials are discussed including the particle (mass) velocity profiles at a number of Lagrangian positions in the flow, progress of the shock front as measured by shock tracker gauges, and the position when the reactive wave reaches a detonation condition. The two-stage gun, in conjunction with the multiple magnetic gauging method, has proven very useful for generating new information in initiation experiments. Information from these experiments is of great value to modelers trying to determine the proper reaction rate models to use in simulations of the shock initiation process