Electromagnetic modeling of hot-wire detonators using analytical and numerical methods with comparison to experiment

The electromagnetic (EM) characteristics of hot-wire detonators are determined in order to quantify more precisely their response to EM illumination. The analyses include a comprehensive study of detonators' physical characteristics, which is then used to model detonators using transmission line theory. The theoretical analysis treats the detonator as a cascaded transmission line incorporating several different dielectrics, and examines both differential and common mode excitation for a generic detonator model. This 1-D analytical model is implemented in MatLAB and used to determine the input impedance of the detonator for a frequency range spanning DC to 9 GHz. This program can then quickly investigate similar hot-wire detonators by varying their parameters.;The generic model of the detonator is also simulated using ICEPIC, a 3-D finite-difference-time-domain (FDTD) full wave numerical EM solver. The ICEPIC simulations are performed at several frequencies for both differential and common mode excitations, and are used to determine EM properties of the detonator. The results of these simulations are compared with the analytical predictions. Both the analytical and numerical techniques are then used to improve the MatLAB program's ability to accurately predict the detonator's EM characteristics. This is accomplished by including additional elements in the 1-D model accounting for detonator properties revealed in the 3-D EM simulation results.;Finally, the analytical model is used to predict the input impedance for state-of-the-art blasting cap. These predictions are then compared with data from experimental measurements performed on 108 live devices.