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The D-T fusion reaction, is the most efficient reaction known in terms of energy released.
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Image courtesy of Plasma Physics Laboratory

Fusion Reactions

Nuclear fusion is a process where two or more nuclei combine to form an element with a higher atomic number (more protons in the nucleus). Fusion is the reverse process of nuclear fission. Fusion reactions power the Sun and other stars.

Fusion releases energy. The energy released is related to Einstein's famous equation, E=mc2.

For a fusion reaction to occur it is necessary to bring the nuclei so close together that nuclear forces become important and "glue" the nuclei together. The nuclear force only acts over incredibly small distances and has to counteract the electrostatic force where the positively charged nuclei repel each other. For these reasons fusion most easily occurs in a high density, high temperature environment.

On Earth, nuclear fusion was first reached in the explosion of the Hydrogen bomb. In a non-desctructive manner, fusion has also been reached in different experimental devices aimed at studying the possibility of producing energy in a controlled fashion.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA