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 |  | Harnessing Prevalent Plasmas
By James Schultz
Special to SPACE.com
posted: 07:03 am ET
25 July 2000
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A kind of gaseous cosmic soup comprised of molecules, atoms, negatively charged electrons and positively charged ions, plasmas comprise 99 percent of the known universe
Plasmas, a kind of gaseous cosmic soup comprised of molecules, atoms, electrons and positively charged ions, make up 99 percent of the known universe.
The three other known states of matter --- solids, liquids and gases --- make up a mere 1 percent.
Plasmas are most commonly found in interstellar space, where residual hydrogen is ionized by radiation, and in stars whose energy-generating efficiencies scientists have long desired to emulate.
In stars, for hydrogen nuclei to fuse into heavier nuclei they must be fast enough to overcome a mutual electric repulsion when the hydrogen ionizes into a plasma. Very hot plasmas overcome these limitations when their constituent particles collide with one another, acquiring sufficient energy to fuse -- and releasing enormous energy in the process. Such reactions are at the literal heart of the sun’s core and, for the next four or so billion years, a ready and abundant source of heat in the immediate solar neighborhood.
Interest in plasma physics initially developed because of radio communications and the effect of Earth’s ionosphere on radio-wave transmission. Because the ionosphere is essentially a plasma, ranging from approximately 50 to 600 miles (80 to 965 kilometers) above the planet’s surface, radio waves are partly absorbed by ionized air and in part refracted, or bent downward. The bending effect makes possible reception at distances much greater than for signals sent in a straight line, ones that could not follow the curvature of the globe.
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