Nuclear physics
Nuclear Fusion
The combination of light atomic nuclei (typically deuterium and tritium) into heavier nuclei, releasing energy.
Fusion powers stars and is the energy mechanism in thermonuclear weapons. In a hydrogen bomb, a fission primary compresses and heats lithium-deuteride fuel to fusion-ignition temperatures (millions of degrees), releasing far more energy than fission alone.
Related terms
Nuclear Fission
The splitting of heavy atomic nuclei (typically uranium-235 or plutonium-239) into lighter fragments, releasing large amounts of energy.
Thermonuclear Weapon
Synonym for hydrogen bomb — a nuclear weapon whose primary energy comes from fusion reactions.
Deuterium
A heavy isotope of hydrogen with one neutron, used as fusion fuel in thermonuclear weapons.
Tritium
A radioactive heavy isotope of hydrogen with two neutrons, used as fusion fuel and in boosted-fission weapons.