lauromuller

Under extremely high temperatures (over ~3.000K) the electrons and protons dissociate, resulting in plasma. But for hydrogen nuclear fusion to happen we need much higher temperatures than this (order of 107 K). How does this process get "inverted"? I mean... If in temperatures higher than 3.000K the protons and electrons dissociate, how is possible that in much higher temperatures they "re-associate"? How are atoms formed during nuclear fusion? Besides, in the beginning of universe expansion, we had the required temperature to fusion.. Why it didn't happen then?