Weapon whose enormous explosive power is generated by the nuclear fusion of hydrogen isotopes. The high temperatures required for the fusion reaction are produced by detonating an atonmic bomb.
The bomb's explosion produces a blast that can destroy structures within a radius of several miles, an intense white light that can cause blindness, and heat fierce enough to set off firestorms. It also creates radioactive fallout that can poison living creatures and contaminate air, water, and soil.
Here is a super cool video I found on Youtube showing some of the hydrogen explosions. Enjoy!