How Hydrogen Bomb Works?

On Wednesday, World leaders scrambled to investigate claims from North Korea that it had developed a hydrogen bomb in violation of United Nations Security Council resolutions. While the communist country has some level of nuclear capability, it wasn't immediately clear that they had successfully built a working atomic bomb. How it is going to work at International and political level of the World is out of scope of our blog, Let's discuss about How the hydrogen bomb work in the World of Nuclear Physics.

Atomic weapons are plutonium-based and involve a process called fission that splits plutonium into smaller atoms, releasing massive amounts of energy. Whereas, Hydrogen bombs are made with uranium. Instead of splitting big atoms, Hydrogen bomb combines small atoms to release a massive nuclear force hundreds of times more powerful than an atomic weapon.

Fusion Reaction

At extremely high temperatures, the nuclei of hydrogen isotopes deuterium and tritium can readily fuse, releasing enormous amounts of energy in the process. Weapons that take advantage of this process are known as fusion bombs, thermonuclear bombs or hydrogen bombs. Fusion bombs have higher kiloton yields and greater efficiencies than fission bombs, but Deuterium or tritium has to be highly compressed at high temperature to initiate the fusion reaction.

Fusion bomb uses lithium-deuteride, a solid compound that doesn't undergo radioactive decay at normal temperature, as the principal thermonuclear material. As Tritium has short half-life, bomb designers rely on a fission reaction to produce tritium from lithium. The majority of radiation given off in a fission reaction is X-rays, and these X-rays provide the high temperatures and pressures necessary to initiate fusion. So, a fusion bomb has a two-stage design -- a primary fission or boosted-fission component and a secondary fusion component.

Hydrogen Bomb Design

To understand this bomb design, imagine that within a bomb casing you have an implosion fission bomb and a cylinder casing of uranium-238 (tamper). Within the tamper is the lithium deuteride (fuel) and a hollow rod of plutonium-239 in the center of the cylinder. Separating the cylinder from the implosion bomb is a shield of uranium-238 and plastic foam that fills the remaining spaces in the bomb casing.

Detonation of the bomb causes the following sequence of events:

1. The fission bomb implodes, giving off X-rays, which heat the interior of the bomb and the tamper; shield used prevents premature detonation of the fuel. The heat causes the tamper to expand and burn away, exerting pressure against the lithium deuterate, which is placed inside it, lithium deuterate is squeezed by about 30-fold. 
2. The compression shock waves initiate fission in the plutonium rod. 
3. The fissioning rod gives off radiation, heat and neutrons. 
4. The neutrons go into the lithium deuterate, combine with the lithium and make tritium. 
5. The combination of high temperature and pressure are sufficient for tritium-deuterium and deuterium-deuterium fusion reactions to occur, producing more heat, radiation and neutrons. 
6. The neutrons from the fusion reactions induce fission in the uranium-238 pieces from the tamper and shield. 
7. Fission of the tamper and shield pieces produce even more radiation and heat. 
8. The bomb explodes.

The result is an immense explosion with a 10,000-kiloton yield -- 700 times more powerful than the Little Boy explosion.