Muzzle Voltage Characteristics of Railguns

Muzzle voltage is an essential diagnostic tool used in both contact resistance modeling and transition determination. However, it is challenging to stem the necessary meanings from the collected measurements. In this study, EMFY-3 launch experiments are used to model muzzle voltage characteristics to understand the transition mechanism better. These experiments have muzzle energies in the range between 1.69-2.85 MJ in ASELSAN Electromagnetic Launcher Laboratory. Six different launch tests with various rail current waveforms that ranged between 1.5-2.1 MA are used to investigate different scenarios. Some parameters which affect muzzle voltage are calculated with the 3-D Finite Element Method (FEM), i.e., rail mutual inductance $\mathrm{L_m}$. Muzzle voltages are decomposed into subsections; each subsection is calculated with proper models. Simulation results are coherent with experimental measurements. Findings are compared with previous studies, and differences are explained with possible reasons. Even though we could not conclusively resolve which physical quantity starts to transition, the study showed that transition does not form a specific muzzle velocity, armature action integral, or down-slope rail current ratio.