Modeling of the exploding foil initiator and related circuitry for the variable mode of operation

Analytical and numerical models, validated against published data, were developed to calculate the velocity and time of arrival duration (ToAD) of the flyer-plasma material at the top of the barrel of an exploding foil initiator (EFI), as commonly used in explosive devices. Such tools will aid system designers in the optimization of capacitor discharge circuit (CDC) or EFI bridge material properties.

The analytical elements of the approach developed support the requirement for the consideration of mass ejection variation with respect to initial capacitor voltage.

The numerical elements of the approach developed demonstrate that EFI design alteration to increase flyer mass is less effective in reducing ToAD than supply voltage modulation via the CDC. This finding is of particular relevance for in situ control of functional performance characteristics. This work goes on to demonstrate that such control is impracticable when using hexanitrostilbene, since the initial capacitor voltages necessary to yield appropriate ToAD for deflagration deliver insufficient energy to instigate a response from the EFI.