Thermonuclear weapon
Thermonuclear weapon

Thermonuclear weapon
The design of all thermonuclear weapons is believed to be the Teller–Ulam configuration. This relies on radiation implosion, in which X-rays from detonation of the primary stage, a fission bomb, are channelled to compress a separate fusion secondary stage containing thermonuclear fuel, primarily lithium-6 deuteride. During detonation, neutrons convert lithium-6 to helium-4 plus tritium. The heavy isotopes of hydrogen, deuterium and tritium, then undergo a reaction that releases energy and neutrons. For this reason, thermonuclear weapons are often colloquially called hydrogen bombs or H-bombs.
Terminology
"Thermonuclear" refers to thermonuclear fusion, where nuclei are fused via their high collision speeds at high temperatures. Unlike fission weapons, whose detonations are mediated via neutron transport, thermonuclear yield is also more directly dependent on the temperatures and pressures achieved during compression of the secondary.