For 10 points, name this device that is more powerful than a standard atomic bomb because it fuses the lightest element.
This device works in part because polystyrene foam turns into plasma when exposed to x-ray radiation. The Russian version of this device was designed by Andrei Sakharov. One American discoverer of this device was a Polish mathematician who also designed a way to travel through space using this device, Stanislaw (+) Ulam. The other was a Hungarian physicist who wanted to use this device to create an artificial harbor in Alaska, Edward Teller. The first of these devices to be tested was codenamed Castle Bravo, and was set off in 1954 at (*) Bikini Atoll. In the United States and Russia, these devices make up most of the modern nuclear arsenal. For 10 points, name this device that is more powerful than a standard atomic bomb because it fuses the lightest element.
This device works in part because polystyrene foam turns into plasma when exposed to x-ray radiation.
{hydrogen} bomb [or {H}-{bomb}; or {fusion} bomb before "{fuses}"; or {Teller}-{Ulam device} before