Neutralization of explosives by plasma jet impingement: Feasibility study

Preliminary results of an experimental study to determine the feasibility of neutralizing explosives by impingement of a high-temperature, high-velocity pulsed plasma jet are presented. The pulsed plasma jet was created by an electrothermal gun, a device that relies upon vaporization of solid metal to produce a metal vapor plasma. The tests were conducted using an aluminum plasma with a pulse duration of I ms and peak energy of 100 kJ on 1-g specimens of PETN explosive. The specimens were placed inside a chamber at standoff distances of 15-30 cm from the 6.65-mm diameter muzzle of the electrothermal gun. The effectiveness of the plasma impingement was determined by comparing postdetonation experiments on the exposed and unexposed explosive specimens. High-speed imaging of the plasma jet impinging on the explosive and postmortem examination of the explosive specimens suggests that three distinct interactions occur. These interactions are: slow thermal decomposition (burning); rapid thermal decomposition (deflagration); and change in chemistry with negligible or no thermal decomposition. Initial results suggest that these three distinct interactions are a function of the mass flow rate and energy of the plasma.