  Large railguns require powerful power supply units. At the French-German
Research Institute of Saint-Louis (ISL) most experimental railguns are driven
by power supply units based on capacitors. Recent investigations at ISL explore
the possibility to use coil based systems to increase the energy density of the
power supply. In this study an electrical circuit simulation is used to
investigate the difference for railgun operation in between a capacitor and a
coil based power supply with respect to current amplitude behavior and
projectile velocity. For this a scenario of a 25 MJ muzzle energy railgun is
simulated with two different power supply options, replacing capacitors by
coils and using a range of circuit resistances. The resistance determines to a
large part the losses of the system and defines therefore the efficiency of the
launch and the size of the power supply. The interpretation of the results of
the performed simulations leads to the conclusion that the capacitor based
system "naturally" pro- duces a favorable current pulse trace with respect to
launching a mechanical delicate payload. Further simulations show that the
disadvantage of the inductor based supply can be mitigated by increasing the
power supply unit subdivision into smaller units.

Plasma Physics;Applied Physics;Instrumentation and Detectors