PROJECT TITLE :

On the Validity of Certain Approximations Used in the Modeling of Nuclear EMP

ABSTRACT:

In legacy codes developed for the modeling of EMP, multiple scattering of Compton electrons has typically been modeled by the obliquity factor. A recent publication has examined this approximation within the context of the generated Compton current [W. A. Farmer and A. Friedman, IEEE Trans. Nucl. Sc. 62, 1695 (2015)]. Here, this previous analysis is extended to incorporate the generation of the electromagnetic fields. Obliquity factor predictions are compared with Monte-Carlo models. In using a Monte-Carlo description of scattering, two distributions of scattering angles are thought-about: Gaussian and a Gaussian with one-scattering tail. Additionally, legacy codes additionally neglect the radial derivative of the backward-traveling wave for computational efficiency. The neglect of this spinoff improperly treats the backward-traveling wave. These approximations are examined within the context of a high-altitude burst, and it's shown that as compared to more complete models, the discrepancy between field amplitudes is roughly 2 to three p.c and between rise-times, tenp.c. More, it's concluded that the biggest issue in determining the increase time of the signal isn't the dynamics of the Compton current, however is instead the conductivity.