We give an overview of how hydrogen bombs work and how they differ to atomic bombs.
State media in North Korea is claiming the country’s leader Kim Jong-un has carried out a “perfect” test of a hydrogen bomb at a nuclear test site in Punggye-ri.
It marks the sixth test by Kim Jong-un in recent years and has been condemned by world leaders as well as the UN.
Hydrogen bombs are said to be 1,000 times more powerful than the atomic bombs dropped during the Second World War and represent a significant escalation in North Korea’s nuclear plans.
A hydrogen bomb is what’s known as a thermonuclear bomb. It is classed as a second-generation nuclear weapon as it uses the processes seen in atomic bombs and advances them to make a more powerful detonation.
In particular, it uses the fission chain reaction seen in an atomic bomb to bombard a fusion bomb with energy that results in a devastating explosion.
The dictionary definition of a hydrogen bomb is “an immensely powerful bomb whose destructive power comes from the rapid release of energy during the nuclear fusion of isotopes of hydrogen (deuterium and tritium) , using an atom bomb as a trigger.”
The US was the first country to develop nuclear weapons, followed by Russia in 1949. The first thermonuclear test, code-named Ivy Mike, detonated on 1 November 1952 on the island of Elugelab in Enewetak Atoll, in the Pacific Ocean, as part of Operation Ivy.
It marked the first full-scale device that created an explosion using nuclear fusion. You can read more about the differences between nuclear fission and nuclear fusion in our nuclear energy explainer.
All nuclear weapons use a process called nuclear fission to generate the energy needed for their explosions. Early weapons, including the Little Boy dropped on Hiroshima, created the critical mass needed to kickstart a fission reaction by firing a hollow uranium-235 cylinder at a target made from the same material.
This technique creates a blast that implodes on itself first, forcing atoms together. Neutrons are then used to create a chain reaction which leads to the outward atomic explosion.
Hydrogen bombs take things a step further and use a process called nuclear fusion to force the atoms together, similar to the extreme process that powers our sun. To create a fusion reaction, you need a vast amount of energy, and in hydrogen bombs, this comes from a fission reaction which means a hydrogen bomb is effectively a fusion bomb and a fission bomb rolled into one.
The fission bomb releases a blast of powerful radiation, using the fission method, and this radiation is then aimed at the fusion bomb. The energy from this radiation is enough to trigger the chain reaction needed for atoms to merge inside the fusion bomb. As the atoms merge, they generate more energy which triggers the second of the two bombs and leads to a more powerful explosion.
In particular, “heavy” isotopes of hydrogen are forced together to release a more substantial release of energy. All modern-day thermonuclear weapons in the United States, specifically, use what’s known as the Teller–Ulam configuration after scientists Edward Teller and Stanislaw Ulam.
Atomic bombs use nuclear fission which splits the nuclei of plutonium and/or uranium into smaller atoms. When neutrons, or neutral particles, of these atoms are split, they hit the nuclei of other nearby atoms, which in turn causes them to split. This generates a chain reaction that releases massive amounts of energy. They are also typically large devices – the Fat Man atomic bomb dropped on Nagasaki in 1945 weighed around 4,700 kilograms.
By contrast, as explained above, hydrogen bombs use a similar fission technique to create the initial chain reaction to provide the ‘fuel’ needed to generate the second chain reaction and cause the fusion bomb to explode. Scientists are working to make hydrogen bombs small enough to sit on nuclear missiles.
The atomic bombs dropped on Hiroshima and Nagasaki exploded with the yield of around 15 kilotons and 20 kilotons of TNT, respectively, according to the Union of Concerned Scientists. During the Ivy Mike hydrogen bomb test, this yield was closer to 10,000 kilotons of TNT.
This article originally appeared at alphr.com
