Nuclear weapon effects
Air Burst
A nuclear detonation above the ground at optimal altitude, maximizing the area affected by blast and thermal radiation while producing minimal fallout.
In an air burst the fireball does not reach the ground, so the bomb cannot vaporize and irradiate soil. This minimizes local fallout but maximizes blast spread because the shock wave reflects off the ground and reinforces the direct wave. Hiroshima and Nagasaki were both air bursts — the optimal altitudes were 580 m and 503 m respectively.
Related terms
Surface Burst
A nuclear detonation at ground level, producing roughly 40-50% smaller blast radius than an air burst but creating massive radioactive fallout.
Fallout
Radioactive material thrown into the atmosphere by a surface-burst nuclear detonation, which then settles back to earth over hours to weeks.
Fireball
The sphere of plasma created by a nuclear detonation, with internal temperatures exceeding 10 million °C — hotter than the surface of the Sun.