Nuclear physics
Second-Degree Burns
Partial-thickness burns affecting both the epidermis and dermis, characterized by blistering and pain.
In a nuclear context, the 2nd-degree burn radius is the distance at which exposed skin receives enough thermal radiation (about 5 cal/cm²) to blister but not char. For a Hiroshima-yield bomb, this radius is roughly 2 km; for a 1 Mt weapon it extends to about 12 km.
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.
Fireball
The sphere of plasma created by a nuclear detonation, with internal temperatures exceeding 10 million °C — hotter than the surface of the Sun.