Burn Propagation in a PBX 9501 Thermal Explosion

We have measured burn velocities in a series of radially heated PBX 9501 thermal explosion experiments. Burn fronts have been imaged in these experiments using proton radiography. The velocities observed imply a convective burn front moving at approximately 200m/s. A compendium of burn velocities verses pressure show two distinct burn mechanisms: convection and conduction. The 200m/s velocity places the PBX 9501 radial thermal explosion experiment in the convective regime with an implied pressure on the order of 1 Gpa. The density evolution observed shows that HE continues to be consumed behind the convective front. The HE consumption follows the approximate radial symmetry of the heating profile. A hypothesis for the material consumption is made based on the implied pressures and material state. Implications for incorporating PBX 9501 thermal ignition and burn into larger scale models are discussed.