Nuclear fusion

Nuclear fusion combines light atomic nuclei into heavier nuclei. It releases energy when the products have greater binding energy per nucleon than the reactants.

Coulomb barrier: The electrostatic energy barrier that positively charged nuclei must overcome to approach closely enough for fusion. Fusion requires nuclei to penetrate this repulsive barrier, often through quantum tunneling.
Stellar nucleosynthesis: The creation of chemical elements through nuclear reactions inside stars and stellar explosions. Fusion builds many elements in stars, beginning with helium from hydrogen.
Atomic nucleus: The dense central part of an atom, composed of protons and neutrons. Fusion changes nuclei rather than rearranging the electrons around them.
Nuclear fission: A nuclear reaction in which a heavy nucleus splits into lighter nuclei, often releasing energy and neutrons. Fission releases energy by splitting heavy nuclei, whereas fusion combines light ones.
Quantum tunneling: A quantum process in which a particle crosses an energy barrier it could not surmount classically. It lets stellar nuclei fuse even when their thermal energies fall below the Coulomb barrier.
Magnetic confinement fusion: A fusion approach that uses magnetic fields to confine hot plasma away from material walls. It is one major strategy for sustaining fusion conditions on Earth.
Strong nuclear force: The fundamental interaction that binds protons and neutrons within atomic nuclei. Once nuclei approach closely, this attraction can overcome their electric repulsion.
Radioactive decay: The spontaneous transformation of an unstable atomic nucleus into a more stable configuration, often emitting radiation. Unlike fusion, radioactive decay does not require two nuclei to collide.
Nuclear binding energy: The energy required to separate an atomic nucleus into its constituent protons and neutrons. Fusion releases energy when the resulting nuclei are more tightly bound per nucleon.
Inertial confinement fusion: A fusion approach that compresses and heats a small fuel capsule rapidly, often with powerful lasers. It seeks brief fusion burn by imploding fuel rather than holding plasma for long periods.

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