A hydrogen bomb is a nuclear bomb, like an atomic bomb, where the explosive energy comes from as nuclear reaction.
A hydrogen bomb is about fusion — fusing atomic nuclei together to combine into bigger ones.
A hydrogen bomb, or a thermonuclear bomb, contains a fission weapon within it but there is a two-stage reaction process.
The U.S. used two atomic bombs in World War II against Japan, Then, in 1952 and 1954
In particular, monitors will be looking for isotopes of a gas called xenon, which is typically present in H-bomb reactions.
