Bild:Plasma-lamp 2.jpg
A plasma lamp, illustrating some of the more complex phenomena of a plasma. The colors are a result of the relaxation of electrons in excited states to lower energy states after they have recombined with ions. These processes emit light in a spectrum characteristic of the gas being excited.

Plasma is a state of matter where the bonds between parts of the atoms are broken and the pieces, electrons and nuclei, separate. Even though they separate from one another, the electrons and nuclei still pull on each other because of their electric charge. This keeps them from getting too far apart, so the plasma stays together. Because the bonds are broken, the electrons can flow and move, so there are many interesting kinds of waves that can travel in a plasma, especially if there is a magnetic field in it. Magnetic fields make free electrons move in circles, and electric fields make them move in straight lines. Putting both kinds of fields into a plasma makes the electrons and nuclei do very complicated things.

Plasmas are usually very hot, because it takes high temperature to break the bonds between the electrons and the nuclei. Sometimes plasmas can have very high pressure, like in stars. Stars (including our own Sun) are mostly made of plasma. Plasmas can also have very low pressure, like in outer space.

On Earth, natural plasma makes lightning and auroras. Artificial (man-made) uses of plasma include fluorescent lightbulbs, "neon" signs, and plasma displays used for television or computer screens. Scientists are experimenting with plasma to make a new kind of nuclear power, called fusion, which would be much better and safer than ordinary nuclear power, and would produce much less radioactive waste—maybe none at all!

## See also

- Gas
- Liquid
- Solid ar:بلازما (فيزياء)

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