Light radiation of nuclear explosion

When a nuclear explosion of the energy (30-40%) is allocated in the form of light radiation, the source of which are the hot products of the explosion and the air. Within a very short time temperature luminous area varies from millions to several thousand degrees.
At high temperatures light richly ultraviolet rays and relatively little contains infrared rays. As the temperature increases, the percentage of infrared rays, and ultraviolet - decreases. Depending on the caliber of nuclear ammunition light flash lasts from 1 to 8 seconds.
The main characteristic of light radiation, acting on an object is the light pulse energy quantity of light radiation incident on 1 m2 surfaces perpendicular to the direction of radiation propagation for all the time of the glow. Its value is expressed in cap/cm2. For nominal bombs light pulse has the following values at different distances from the center of explosion: at a distance of 200 m -10 cal/cm2; 300 m - 3 kcal/cm2 400 m - 2 cal/cm2.
Light pulse 10 cal/cm2 is a matter of deep burns, spontaneous combustion dark materials, dry wood and charring of white paper.
Light pulse 2-3 cal/cm2 (3-4 km from the place of explosion)-causes burns of I-II degree and charring dark fabrics. In the zone of 1.5-2 km you charring uncovered body parts, and the animals of the ears, the tail, the udder and other speakers, especially hairless body parts. In the area of 2-3 km prevail burns of II-III degree.
According to Hatano and Watanuki (quoted from the drug of choice Harada), the frequency of burns in the explosion of the atomic bomb in Hiroshima on different distance from the hypocenter was the following:

0-0,5 km - 0%
0,6-1,0 km was 14.8%
1,1-1,5 km -60,8%
1,6-2,0 km -85,0%
2,1-2,5 km -72,8%
the 2.6-3.0 km -26,9%
3,1-3,5 km -11,1%
the 3.6-4.0 km -0%
Low percentage of burns among persons who were at a distance less than 1 km from the hypocenter, due to the fact that most of those who were in the area, were killed.
According to the report, Suzuki, the medical team of the Tokyo Imperial University at rendering aid to the victims in Hiroshima surveyed between October and December 1945 5120 injured, including 1881 people (36,7%) had burns.
Objects not fully absorb the incident light radiation, part of it they reflect, or, if they are transparent,-miss. So, glass passes 90% of all energy; black surfaces absorb 90-99% of all energy, and white-only 10-30%. Therefore, the white surface in 2-3 times more stable compared to black. The surface layer is opaque object, absorbing the bulk of light radiation, heated to high temperature, and the thinner the layer, the higher the temperature of heating. Having poor heat conductivity, animal tissues absorb light radiation of a thin surface layer, which gets very hot, resulting in the formation burns.
From snow, ice, water, clouds and other objects is recorded about 50% of light energy, which in turn can strengthen the striking effect of light radiation on animals in the vicinity of the reflective surface.
Due to the fact that light is distributed straightforward and much is absorbed by objects, - it is relatively easy to defend. All non-transparent objects protects animals from burns. Well also protect from influence of light radiation collective means of protection of animals, forest, Bush and ravines. So, a rare broad-leaved forest weakens light pulse in 2-3 times, and thick - up to 10 and more times. With increasing distance from the center of the explosion, the magnitude of the light pulse decreases rapidly: it absorbs the airborne dust particles. Therefore, the more dusty air, the more attenuated light radiation.
Formed under influence of light radiation burns are characterized by: the duration of healing, the formation of keloids - dense scar skin, acting on 1-2 cm above the surface, as well as the ability of those scars to cancer rebirth.