Nuclear fusion is a particular process in nuclear physics in which two light atoms fuse to form a larger atom. This process is fascinating to the scientific world because it releases a large amount of energy.
Nuclear fusion is a type of reaction that alters the structure of atoms that occurs in space but is very difficult to reproduce on Earth. Let's see some examples:
The sun and the stars
The most prominent examples of nuclear fusion in nature are found in stars, including our Sun. Nuclear fusion is the process that powers stars, releasing enormous amounts of energy in the form of light and heat.
The fusion process in stars mainly involves the fusion of hydrogen into helium through a series of nuclear reactions.
In the core of the Sun and other similar stars, fusion reactions occur mainly as follows:
Proton-proton fusion: In this reaction, two hydrogen nuclei (protons) combine to form a deuterium nucleus, releasing a positron (antiparticle of the electron) and a neutrino. The deuterium then fuses with another proton to form a helium-3 nucleus, releasing a gamma photon.
Deuterium-hydrogen fusion: In this reaction, a deuterium nucleus fuses with a hydrogen nucleus to form a helium-3 nucleus, releasing a gamma photon.
Helium-3-helium-3 fusion: Two helium-3 nuclei combine to form a helium-4 nucleus and two protons. This reaction is one of the pathways for the production of helium-4 inside stars.
These fusion processes release a large amount of energy in the form of electromagnetic radiation (gamma photons) and particles, which heat the stellar core and keep the star in a balance between gravity that tends to collapse it and the pressure generated by the fusion that keeps stable.
Nuclear Fusion Research Reactors
On Earth, large-scale controlled nuclear fusion for power generation has not yet been achieved. However, research and experiments are being carried out in fusion reactors to develop technologies to harness fusion as a clean and sustainable energy source in the future.
Some of the major projects in this regard include ITER, the JET (Joint European Torus) and other research reactors.
The H-bomb or thermonuclear bomb
The hydrogen bomb, also known as the H-bomb or fusion bomb, is a valid example of nuclear fusion. The hydrogen bomb is one of the most powerful nuclear weapons in existence and works through the process of nuclear fusion.
Unlike traditional atomic bombs, which are powered by nuclear fission (the splitting of heavy atomic nuclei), the hydrogen bomb uses nuclear fusion to release its destructive energy. Inside a hydrogen bomb, a fission chain reaction begins, providing the energy and extreme conditions necessary to initiate fusion.
The main process that occurs in a hydrogen bomb is the fusion of hydrogen nuclei (deuterium and tritium isotopes) to form helium and release an enormous amount of energy in the form of radiation and shock waves. This massive release of energy is what causes the characteristic destructive explosion of the hydrogen bomb.
To this day, the hydrogen bomb has never been dropped on any military or civilian target. The only two nuclear bombs dropped were those on Hiroshima and Nagasaki designed in the Manhattan Project led by physicist Robert Oppenheimer.