Fusion thermal weapon would be a multistage nuke. It's trigger is a fission Nuke, like the Hiroshima weapon. Shaped explosive charges around a ball of highly enriched plutonium that causes it to reach critical mass.
Using the energy from the trigger to fuse tritium and deuterium which releases a massive amount of energy and also as a by-product Hydrogen.
Thus a "Hydrogen Bomb". Kilotons to Mega-tons is the difference.
The tragedy is not that things are broken. The tragedy is that things are not mended again. - Alan Paton
Bach is the beginning and end of all music - Max Reger
It is not God who kills the children. Not fate that butchers them or destiny that feeds them to the dogs. It's us. Only us - Rorschach
Personally, I think the actions of the North Korean leadership are typical of a nation on the verge of an internal revolution. It is quite possible that Kim Jong Un is about to be overthrown by some military strong-man who has sufficient support to pull it off. Kim Jong Un did, if I recall correctly, fire a bunch of military leaders when his father died and he took over. One or some of them may have more support from the military than Un does.
I don't believe that North Korea represents any serious threat to the continental US, but the west's allies in the area, South Korea and Japan, could suffer some of the fallout.
I hate war, and I hate having to be even slightly concerned with what some immature, power mad dip**** thinks about anything.