Electro-muscular disruption (EMD) devices such as TASER M26 and
X26 have been used as a less-than-lethal weapon. Such EMD devices
shoot a pair of darts toward an intended target to generate an
incapacitating electrical shock. In the use of the EMD device,
there have been controversial questions about its safety and
effectiveness. To address these questions, we need to investigate
the distribution of the current density J inside the target
produced by the EMD device. One approach is to develop a
computational model providing a quantitative and reliable analysis
about the distribution of J. In this paper, we set up a
mathematical model of a typical EMD shock, bearing in mind that we
are aiming to compute the current density distribution inside the
human body with a pair of inserted darts. The safety issue of
TASER is directly related to the magnitude of |J| at the region
of the darts where the current density J is highly
concentrated. Hence, fine computation of J near the dart is
essential. For such numerical simulations, serious computational
difficulties are encountered in dealing with the darts having two
different very sharp corners, tip of needle and tip of barb. The
boundary of a small fishhook-shaped dart inside a large
computational domain and the presence of corner singularities
require a very fine mesh leading to a formidable amount of
numerical computations. To circumvent these difficulties, we
developed a multiple point source method of computing J. It has
a potential to provide effective analysis and more accurate
estimate of J near fishhook-shaped darts. Numerical experiments
show that the MPSM is just fit for the study of EMD shocks.