Can any element but hydrogen form plasma, how much energy is needed to completely strip a heavier element of its electrons? I also wondered, if they blew up one of those hydrogen bombs over the sea, what would stop the reaction from spreading? Ok the eaisest way to get plasma is hydrogen because it is the simplist atom, you would need for times more energy to do it for helium(im not even sure if the sun could do that) im not sure how much energy but since stars are the only things that can natually do it I would say a lot. And about hydrogen bombs, I dunno what would happen if you put it in the sea, the energy might actually split the water atoms, feed it with more hydrogen and cause a massive unstopable chain reaction, or it would cool it down so much that it would stop it all together.