TITLE:
Electromagnetic Waves from TNT Explosions
AUTHORS:
A. L. Kuhl, D. A. White, B. A. Kirkendall
KEYWORDS:
TNT Detonation, Boronin Current, EM Waves, Time-Domain Green’s Function
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.6 No.10,
September
24,
2014
ABSTRACT: Experimental
observations indicate that electromagnetic (EM) radiation is emitted after the
detonation of high explosives (HE) charges. The movement of ionized atoms,
particles and electrons seems to be the underlying cause. Expansion of the
detonation products (DP) drives a strong (~1 kb) shock in surrounding air. This
forms an intense thermal wave (T ~11,000
K) with duration of ~20 microseconds. Such temperatures create significant
ionization of the air. According to Ohm’s Law, movement of ionized patches
generates current; and according to the Biot-Savart Law, such currents induce
electric and magnetic fields. We investigate these effects through numerical
simulations of TNT explosions. A high-order Godunov scheme is used to integrate
the one-dimensional conservation laws of gasdynamics. An extremely fine grid
(10 microns) was needed to get converged temperature and conductivity profiles.
The gasdynamic solution provided a source current, which was fed into a
time-domain Green’s function code to predict three-dimensional electromagnetic
waves emanating from the TNT explosion. This analysis clearly demonstrates one
mechanism—the Boronin current—as the source of EM emissions from
TNT explosions, but other mechanisms are also possible.