This is about 5 megajoules, depending on the energy loss. “All that plasma that you see when the gun erupts, that’s material from the rails and sabot being vaporized at the sliding contact".
The railgun pulse power system by Raytheon has diamond heat spreaders and manifolds that have a high density of embedded micro-fins to spread the heat very efficiently away from the small point heat sources and move them through things like graphite and aluminum graphite to the edges of cold rails, so that coolant can be circulated at that point and brought back to a chiller.
3D manufacturing could be used for packaging the inductor and capacitor into a very small size while also providing some of the insulating capabilities that you can get by printing dielectrics.
Engineering at the molecular scale, and future breakthroughs in dielectric materials, will enable more efficient railguns that could make their way onto a wider variety of naval platforms.
SOURCE - Defense One