Electromagnetic-Induced Thermal Decomposition of RDX

We recently discovered that electromagnetic (EM – 2.45 GHz) energy perturbs the thermal ignition mechanism of a common energetic material. We hypothesize that the EM energy 'pumps' the gas-phase charged species that form as part of the pre-ignition process, resulting in accelerated reactions without uniformly heating the volume. Here, we investigate the behavior of RDX exposed to short pulses of EM energy after heating to temperatures below the threshold for thermal decomposition. We have constructed a temperature-controlled experiment to expose the sample to strong electric fields (~ 1 MV/m). Emission was monitored by visible and infrared sensors. The photonic response time was on the order of milliseconds. A theory-based model developed for a similar system shows a comparable temporal response and suggests a mechanism where EM energy accelerates the gas-phase, heat producing reactions, ultimately increasing the heat feedback to the rate-limiting surface reactions. These observations support our hypothesis and illuminated the heat feedback mechanism. Future work will refine the model specifically for the system presented here and expand to include the explosives. HMX and PETN.