Nuclear weapon effects
Fireball
The sphere of plasma created by a nuclear detonation, with internal temperatures exceeding 10 million °C — hotter than the surface of the Sun.
The fireball forms within microseconds of a nuclear detonation as the X-ray flux from the bomb superheats the surrounding air into plasma. Within the fireball radius, everything is vaporized; the plasma sphere also acts as the source of the thermal radiation pulse and the initial blast wave. Fireball radius scales roughly with yield to the 0.4 power.
Related terms
Thermal Radiation
The intense pulse of light and infrared radiation emitted by the fireball of a nuclear detonation, capable of causing burns and igniting fires at long distances.
Overpressure
The pressure above atmospheric pressure produced by the blast wave of a nuclear detonation, measured in pounds per square inch (PSI).
Air Burst
A nuclear detonation above the ground at optimal altitude, maximizing the area affected by blast and thermal radiation while producing minimal fallout.