Transient E-Field Measurements as Test Diagnostics

Signals of various types are of interest to DTRA and DOD for conventional explosives testing. Past work has identified various general mechanisms by which the detonation of conventional explosives produces electric and electromagnetic phenomena. These mechanisms include early time ionization, case breakup, piezoelectric effects, lightning in the debris cloud, seismo-electric effects, and movement of charge within porous earth materials. These phenomena are related to seismo-electric exploration as well as the field of magnetotellurics. Using transient electric field measurements as a test diagnostics tool is attractive because 1) a major advantage of electric methods compared to mechanical methods is that they eliminate the ambiguity that often exists for mechanical signals regarding the travel path and/or propagation velocity (since electric signals propagate at the speed of light, the travel time is insignificant), and 2) valuable data can be collected and analyzed in future tests if it can be determined how the electric field measurements can be related to phenomena of interest. Triton proposes to expand on its e-field measurement capabilities to capture blast propagation data (to include: velocity, intensity and duration). In Phase I, Triton will identify the most important mechanisms that generate transient electric fields during explosive tests, and the signal types and characteristics expected from such mechanisms. Triton’s arguments will be testable and support using methods such as: theoretical derivations, modeling, previous studies, and simple experiments (if cost feasible). Triton’s best method or methods to collect transient electric field measurements during explosive tests will be proposed. In Phase II, Triton will execute an experimental test program to verify mechanisms identified in Phase I, incorporating the measurement method(s) proposed in Phase I. Triton’s experimental test program willincorporate pre-test predictions.