How does a hydrogen bomb work and how is it different from an atomic bomb?

Answer 1

A hydrogen bomb works by fusing hydrogen isotopes, the product weighing less than the initial hydrogen isotopes. The difference in weight is released in energy. Its the same way the sun works. An atom bomb works by splitting a fuel apart on the atomic level, like plutonium or enriched uranium. An H-bomb is a lot more powerful, in the mega ton range.

Answer 2

A hydrogen bomb works by fusing hydrogen isotopes, the product weighing less than the initial hydrogen isotopes. The difference in weight is released in energy. Its the same way the sun works.

An atom bomb works by splitting a fuel apart on the atomic level, like plutonium or enriched uranium.

An H-bomb is a lot more powerful, in the mega ton range.

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"Atomic bomb" is ambiguous and could mean either a fission bomb or any nuclear bomb including a fusion (Hydrogen) bomb, though the former is often assumed.

A fission bomb uses a conventional chemical explosive to create a supercritical mass of certain metals that have unstable nuclei (like Uranium 235 or Plutonium 239). It usually does this by "imploding" a sub-critical mass of the metal and crushing it to such a density that it becomes super-critical (the critical mass is smaller when density is higher). When a supercritical mass is of the metal is achieved, neutrons start a chain reaction that splits the atoms in the metal releasing large amounts of energy and several additional neutrons that will in turn split more atoms, and so on, with more and more energy being released until the bomb finally blows itself apart.

The other main type of nuclear weapon is the fusion bomb. Commonly called the H-bomb, the hydrogen bomb, or the thermonuclear bomb, the fusion bomb relies on the fusion of light isotopes (usually of hydrogen and sometimes helium) to create a large amount of its energy. This is different from fission bombs, that release energy but inducing a neutron chain reaction to split large atoms in metals like Uranium 235 and Plutonium 329. The fusion bomb was invented in the decade after the first nuclear weapons were designed in the early 1940's.

The fusion bombs in use today all rely on a fission bomb first stage (called a "primary") to compress and heat a second fusion stage (called a "secondary"). The second stage has a thick shell of dense metal (which can be a fissionable metal, but need not be) on the outside and is filled with fusion fuel (hydrogen isotopes, or more usually a lithium-hydrogen compound [LiD]). It is usually round. In the center of the fusion fuel is another piece of fissile metal (usually Plutonium 239) called a "spark plug." These two stages are placed inside a case of dense metal, usually shaped like a peanut, with one stage at each end.

When the fission primary goes off, x-ray radiation floods down around the fusion secondary instantly heating its metal shell and causing it to implode inwards as it outer layers explode away. This is called "radiation implosion." As the shell of the secondary implodes, it compresses both the fusion fuel and the "spark plug." The "spark plug" quickly is crushed to such a density that it is supercritical and it fissions and explodes against the fusion fuel which is still being crushed inward by the radiation implosion. The effect is that the fission primary is pushing inward on the secondary while the spark plug (basically another fission bomb) explodes outward--the fusion fuel is caught between. That fuel is heated and compressed (and any lithium transmuted) to such a degree that fusion can finally occur. The lite isotopes fuse and some mass it converted in to huge amounts of energy. A large number of fast neutrons are also produced. if the casing of the bomb or the metal shell of the secondary are made of uranium of thorium of a similar fissionable metal, these neutrons will fission the metal producing even more energy (this can almost double the yield in designs that use such metals as well as increasing fallout dramatically.) It is possible to add additional fusion stages, (which has been done in practice), though any number of additional ever-larger stages is possible.

Thus, theoretically, a fusion bomb of unlimited size can be build. While most nuclear weapons existing today are fusion designs, most of them are no larger than the largest fission bomb (500kt), since military needs actually favor smaller weapons over big yields.

All of the biggest nuclear bombs ever built have been fusion bombs. The largest bomb detonated was a fusion bomb that was equivalent to 50 million tons of TNT. The largest fission bomb tested was only one 100th as powerful, yielding 500 kilotons (half a million tons of TNT), which is still more than 20 times more powerful than the weapon dropped on Nagasaki.

A fission bomb is used to compress a core of hydrogen isotopes. The heat and compression cause the hydrogen isotopes to fuse to form helium and this releases energy from the mass loss involved.

Answer 3

As the term Atomic Bomb can be ambiguous (it means simply any bomb that obtains its energy from atomic nuclei and thus includes the Hydrogen Bomb too) I will assume you really meant a pure Fission Bomb.

The chemical reactions in both pure Fission Bombs and Hydrogen Fusion Bombs are exactly identical: the detonation of chemical explosives used to rapidly assemble a supercritical mass of fissile material from a subcritical mass of fissile material. Once a supercritical mass has been assembled the nuclear fission reaction can be initiated by a burst of neutrons from a neutron source. A Fission Bomb primary is used to trigger the Hydrogen Fusion Bomb's secondary, where the nuclear fusion reaction occurs.

The reactions that produce the actual explosive yield in each type of bomb (fission and/or fusion) and are different, however are purely physical reactions inside atomic nuclei and in no way involve chemistry.