OK, what about plasma weapons in space?
The problems associated with trying to push a self-contained blob of plasma through atmosphere would be greatly lessened in space for obvious reasons, but the energy requirement also ratchets up significantly. Plasma weapons in sci-fi are normally described to have yields in the range of kilotons, megatons, or even higher. They need such yields, in order to compete with guided nuclear-tipped missiles over which they suffer from substantially increased technological difficulties and few if any advantages. Let us examine a hypothetical plasmoid with a yield of 1 megaton and an approximate volume of 1 million cubic metres (which is quite huge for a plasma blast, being comparable to the volume of a small starship). If we assume we’re using hydrogen plasma with average particle energy of 100 keV (an absurdly high temperature of nearly eight hundred million Kelvin), you would need 2.6E29 ions (roughly 215 kg) to get 1 megaton yield (4.2E15 J). Using the ideal gas law, the pressure in this hu
