According to the periodic table of chemical elements only such a number of elements can be in a given volume, which is a Postulate I of the continuation of Einstein's Theory of Relativity; where the Standard Model sets the standard for the smallest element, a photon. (The continuation is a quantitative theory because it uses quantities, not distance-speed-energy.) Thus when tritium and deuterium atoms are decomposed into elements (through laser strikes, that is by photons), the elements return to the structure that is set by the volume of hohlraum ("the hohlraum holding the pallet of fusion fuel, a frozen mix of hydrogen isotopes"). Apparently, the volume of the hohlraum determines that these elements, according to the Poincare Recurrence Theorem/ Postulate I of the continuation of Einstein's theory, become helium atoms. Meanwhile the extra (probably photons, although there may be particles) give the energy output.
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