What is fusion

What is Fusion?

Fusion: When two atoms are pushed together hard enough they can join (fuse) and make a larger, heavier atom. However, the mass of the new bigger atom is less then the sum of the mass of the two old atoms. This extra "missing" mass has become energy by Einstein's famous Equation E=mc²

Plasma: The Fourth State of Matter. Most materials have three well known "states of matter", Solid, Liquid and Gas. Normally, a material changes from a solid to a liquid and then to a gas when heated. For example ice melts and changes to water when heated and water boils and changes to steam when heated. When a gas is heated it can change to the "Fourth State of Matter" a Plasma. A plasma is an "Ionized" gas which is a material which is so hot that the atoms lose some of their electrons and become electrically charged.

Fusion verses Fission: In Fusion, two light (less massive) atoms, like hydrogen, join together to make a heavier (more massive) atom, like helium, while in Fission a heavy atom splits apart into two lighter atoms. To get energy out of the fusion reaction the atoms joined together have a fairly low mass. Fusing heavier atoms takes more energy then it gives. Fission is just the opposite, very massive atoms, uranium for example, give energy when splitting while a lighter atom would take energy to split.

We would like to thank the DIII-D Fusion Education team for allowing us to use some of their figures.

This was last changed on 11 Nov 1998

This page is maintained by David Newman