D⁺, or deuterium ion, is a positively charged ion formed from deuterium, an isotope of hydrogen that contains one proton and one neutron in its nucleus. This ion is represented as D⁺ because it has lost one electron, resulting in a net positive charge. Deuterium is naturally found in small amounts in water and is often used in scientific research and nuclear fusion processes. In the context of nuclear fusion, D⁺ plays a significant role as it can participate in reactions that release large amounts of energy. These reactions are of interest for potential applications in nuclear energy and fusion reactors, where harnessing energy from light elements like deuterium could provide a cleaner and more sustainable energy source.