Thermonuclear fusion is the process by which atomic nuclei combine to form heavier elements and release energy. The spelling of this word can be explained using the International Phonetic Alphabet (IPA). The first syllable, "thermo," is pronounced with the voiced dental fricative /ð/ followed by the vowel /ɜː/. The second syllable, "nu," is pronounced with the vowel /uː/. The third syllable, "cle," is pronounced with the consonant cluster /kl/ followed by the vowel /iː/. The final syllable, "sion," is pronounced with the consonant cluster /ʃn/. Together, these sounds create the word "thermonuclear fusion."
Thermonuclear fusion, commonly referred to as simply fusion, is a nuclear reaction in which light atomic nuclei combine to form a heavier nucleus, releasing a tremendous amount of energy in the process. It is the process that powers the sun and other stars, where hydrogen nuclei collide with enough force and heat to merge and create helium.
This phenomenon occurs under extreme temperature and pressure conditions, often achieved through the use of powerful magnetic fields or lasers. In fusion reactions, the nuclei approach each other closely enough that the strong nuclear force attracts them, overcoming the natural repulsion between positively charged protons. As they come together, they release a significant amount of energy in the form of light and heat.
The energy produced by thermonuclear fusion is substantially greater than that produced by other means, such as chemical reactions or even nuclear fission, which is the splitting of heavy atomic nuclei. Due to this immense energy release, thermonuclear fusion is considered a highly promising source for clean and sustainable power.
Despite its potential, controlling and sustaining thermonuclear fusion on Earth has been challenging. Numerous research projects, like the tokamak and stellarator, aim to replicate the conditions necessary for fusion to occur, with the hope of harnessing this unlimited source of energy for future use. The development of thermonuclear fusion technology could revolutionize the world's energy production and mitigate the growing concerns surrounding climate change and fossil fuel depletion.
The word "thermonuclear" comes from the combination of two Greek roots: "thermo", meaning heat, and "nuclear", referring to the nucleus of an atom. "Fusion" originates from the Latin word "fusio", meaning the act of melting or joining together.
The term "thermonuclear fusion" was coined to describe a process where high temperatures (thermo) and immense pressures cause the fusion (joining together) of atomic nuclei to release huge amounts of energy. This term was specifically created to distinguish it from "nuclear fission", which is the splitting apart of atomic nuclei in processes like those used in atomic bombs or nuclear power plants.