I would not worry about this..
Similar conditions were achieved already: first, during the fusion bomb explosion.
Then, in Tokamaks, but on the much, much smaller scale, and the energy output was smaller that input.. Yes, powers involved were huge, but Power = Energy/time... so, if those processes lasted for couple on nanoseconds, energies involved were miniscule (except in case of nukes)
And all this was achieved without any ether and other "etheric" substances, just plain ol' and boring quantum mechanics and particle physics.
