what is fusion in chemistry

Fusion is a process in which two light atomic nuclei combine to form a single heavier nucleus while releasing massive amounts of energy. This process takes place in a state of matter called plasma, which is a hot, charged gas made of positive ions and free-moving electrons. The sun, along with all other stars, is powered by this reaction. To fuse, nuclei need to collide with each other at extremely high temperatures, around ten million degrees Celsius, which provides them with enough energy to overcome their mutual electrical repulsion. Once the nuclei come within a very close range of each other, the attractive nuclear force between them will outweigh the electrical repulsion and allow them to fuse. For this to happen, the nuclei must be confined within a small space to increase the chances of collision. The energy released by fusion can be harnessed to produce electricity, but a controlled fusion reaction has yet to be fully demonstrated due to many problems that present themselves including the difficulty of confining the plasma.