In-bore electric and magnetic field environment

A jointly sponsored ARDEC-ARL effort is under way to investigate and evaluate the electromagnetic (EM) field environment to which launch package electronics will be exposed during EM launch. In addition, exposure trials were performed on electronic circuit components, with diagnostic tests conducted before and after exposure to establish that the hardware is working properly or to ascertain the existence/nature of an induced malfunction. Tests for the in-bore environment are conducted for a stationary armature in a short section of a 50 mm railgun. Two contact states are studied: solid and arcing (i.e., transitioned). The magnetic field ahead of the armature is measured as a function of axial position. The measurements are made in the same location where the circuit components are located. A 500 MHz high voltage probe is used to measure the voltage at the muzzle of the railgun, and the electric field is measured outside the gun bore. Based on these measurements, the in-bore electric field content is inferred. Both the electric and magnetic fields are evaluated, based on their spectral content and electronic circuit component functionality.