What process does nuclear fusion refer to?

Nuclear fusion is the process in which two light atomic nuclei combine to form a heavier nucleus. This process is the fundamental reaction that powers stars, including our own Sun, where hydrogen nuclei fuse together to create helium under immense pressure and temperature. During fusion, a large amount of energy is released according to Einstein's mass-energy equivalence principle, which states that a small amount of mass can be converted into a significant amount of energy.

This energy release is a key characteristic of fusion, distinguishing it from other nuclear processes like fission, where heavy atomic nuclei split into smaller fragments. Fusion requires specific conditions, typically involving high temperatures and pressures, which facilitate the overcoming of the electrostatic repulsion between the positively charged nuclei. This contrasts with other processes mentioned, such as radioactive decay or particle acceleration, which describe different phenomena in nuclear and particle physics.

Understanding the mechanics and the energy output of nuclear fusion is critical for developments in both astrophysics and potential clean energy sources for humanity, as achieving controlled fusion on Earth could provide a virtually limitless supply of energy.