How a hydrogen bomb blows up

http://www.johnstonsarchive.net/nuclear/nukergv.html which is copyrighted by Robert Johnston, pasted as fair use in my printed, comb-bound John's Technical Interests Growing Up in the Cold War and Space Race at p. 23. Johnston's article is a remarkable piece. It is set in South Texas, so Texans can really relate to the real malls and schools. It talks calmly about violence done to human bodies and leaves the human suffering to other literature.

Reference

Nanoseconds are very short, light travels about a foot in a nanosecond. 1000 nanoseconds = 1000 ns = 1 μs. 1000 μs = 1 ms. 1000 ms = 1 second. Example: 14.7 s means 14.7 seconds

Richard Rhodes The Making of the Atomic Bomb, Dark Sun

Using Johnston's work, which is a fiction piece, derive a timeline for the fusion explosion, detonated at 1.3 mile altitude. The weapon is a 1980s Russian MIRV.

Timeline

Zero time high-voltage charges dump onto the detonator wires from energy-storage capacitors

3 ns detonators start the high-explosive (HE) shock waves

10 μs shock waves reach the first sphere of metal in the small primary (fission) bomb

13 μs 5" diameter, enriched-uranium sphere starts symmetric compression. At 5" diameter, the uranium does not constitute a critical mass.

19 μs 5" diam becomes 2" diam, super-critical. This is 16x density. Neutrons fire in from a source to start the fission chain reaction.

For readers not knowledgeable about compression, compression of a solid or a liquid is a Herculean thing to bring about. If you hit a nail with a hammer, there is a tiny shrinkage of the length of the nail for 10 microseconds, maybe one part in 100,000. Another example: the vertical steel columns of a 50-story, steel-framed building compress a little due to all the weight on them. If the weight could be relieved, the compression would relax and the building would get only about 1/4" taller. Another example: if the weight on the ocean above a deep trench didn't compress the water, the water would be only about 1/2" higher.

The compression accomplished in an atomic bomb implosion is a large compression of strong metal, uranium or plutonium, making the volume 15% less or even 96% less. It is a transient effect, the volume regains normal size after the implosion, but really it doesn't because compressing something so much is applying a tremendous force through a distance, which is work or Joules as one learns in high-school physics. The Joules is so much that the temperature of the metal is raised way above its vaporization temperature. Yes, the uranium or plutonium vaporizes in about 3 microseconds during the implosion, and yet the implosion is so finely tuned that the vaporized metal keeps a spherical shape as it is squeezed down.

The force to do these amazing compressions is available from "high explosives," HE, which includes cordite and plastic explosive. Regular TNT is powerful but no where near as powerful as HE. Most HE is manufactured as a hot slurry and poured into molds. Imagine working around heated high explosive chemicals! If you want to learn more about this, look up shaped charge, which is what anti-tank explosives are, able to punch through military armor plate.

19.1 μs Aided by deuterium and intensely radioactive tritium, 80 generations of chain reaction take place in .1 μs. 20 million °C

19.103 μs gamma-ray pulse reaches weapon case. All the atoms of the weapon are now ionized, gaseous plasma but are heavy enough that they don't move very far, yet; inertial confinement.

19.2 μs In the secondary, the 10" diam. Lithium Deuteride (LiD) cylinder compresses to 2" diam. This is 25x density. Also, neutrons from the primary fission get into the central uranium rod, fissioning it and compressing the LiD cylinder from the inside, too. There is fusion for 1 μs until the LiD expands and halts fusion for lack of density.

The only other place fusion is happening is the centers of stars, where temperature and density produce continuous fusion, but at a slow rate; stellar fusion of nuclei produces less energy per volume than the chemical metabolism of a human body.

20 μs Temperature is 300 million °C. The U238 tamper, initially 1" thick, over the LiD cylinder, fissions for .1μs to double the energy. Total yield is 900 kton, 900 thousand tons of TNT, a smallish hydrogen bomb.

Gamma pulse has reached to 400 meters radius. Some gamma is absorbed by air and re-radiates as hard X-rays. Ionized air contributes to the growing fireball but is conductive and bottles up (reflects) radiation like a mirror. The surface of the fireball emits the first visible flash to be seen by people.

700 μs fireball is 65 m radius

80 ms blast wave separates from fireball, travels initially at mach 10. Fireball is .6 mile diam., surface is cooling with expansion through ultraviolet radiation toward visible radiation.

Thermal radiation starts as ionization of air reduces.

Blast wave enters the ground and starts a shock wave in the ground, kicking up thousands of tons of dirt and debris, much of which vaporizes. Debris is sucked toward ground zero by hurricane-force wind as the hot, buoyant fireball, practically a vacuum, starts to lift like a helium balloon.

1.07 s fireball 1.1 mi. diam. The second visible flash is released.

1.9 s from any water at the surface, up to 8" of it flashes to steam. The water in concrete flashes to steam and explodes the surface of concrete.

8 s fireball stops expanding at 1.3 mi. diam. and reaches ground level. 90% of thermal energy has been released.

Debris sucked into rising fireball is irradiated and some of it becomes radioactive, this will add to fallout. Dusty debris becomes condensation centers for the uranium that remains unfissioned and all the other radioactive vapors, another component of fallout. Much fallout will stay up in the air until it is rained out, up to thousands of miles away, and then there will be concentrations of fallout on the ground and in lakes and rivers.

2.5 miles from ground zero, a few people who are inside buildings will survive the gamma radiation and blast, which arrives at 7.2 s.

Radiation sickness will kill most at this distance, but with treatment some can survive. The trouble is that with hundreds of thousands of victims in an urban setting, and with communications and transportation wiped out, rescue teams have a hard time getting in. If there is general war with nuclear bombs, like a World War III, there are so few rescuers and so many victims that there won't be any help to come in. If Los Angeles is hit, they have a specially hard time since LA is surrounded by mountains and isolated by deserts.

2.9 miles 1% of people survive, most die as buildings are crushed

4.3 miles people who are outside find their skin burning upon a second or two of exposure to the heat radiating from the fireball. Clothing, paint, and plants burn. Blast arrives at 14.7 s.

9 miles black auto tires ignite, clothing ignites when it is exposed for 5 seconds, skin is burned to second or third degree

23 miles at 1 min 43 s, glass windows blow in and lacerate people, fatally for people who have run to windows in curiosity after seeing the flash or feeling building foundations tremor at 23 seconds

40 miles glass windows blow in. Half a million people are dead in a mixed rural/urban setting, many trapped by fires and unable to crawl out. Large urban zones experience conflagration.

400 miles blast is heard after 31 minutes