hélium3

Helium-3 is a stable isotope of helium with two protons and one neutron in its atomic nucleus. Its chemical symbol is ³He. It is distinguished from the more common isotope, helium-4 (⁴He), which has two protons and two neutrons. Helium-3 is significantly less abundant on Earth than helium-4, primarily being a byproduct of tritium decay. It is found in much larger quantities on the Moon, where it is believed to have been deposited by solar winds over billions of years.

The unique properties of helium-3 make it a subject of scientific interest. In its liquid form at very low temperatures, it exhibits superfluidity, flowing without viscosity. This phenomenon, along with the properties of liquid helium-4, was a key area of research for Nobel laureates Pyotr Kapitsa, Fritz London, and Lev Landau.

There is considerable scientific and speculative interest in the potential uses of helium-3. One of the most discussed applications is its possible role as a fuel for nuclear fusion reactors. The reaction between helium-3 and deuterium, a hydrogen isotope, is a potential aneutronic fusion reaction, meaning it would produce fewer neutrons than other fusion processes. This could lead to more efficient and less radioactive fusion power generation. However, the scarcity of helium-3 on Earth and the technological challenges of achieving controlled fusion remain significant obstacles to this application. Other proposed uses include neutron detection and as a component in some advanced medical imaging techniques.