Editing Plasma window (section)

{{Short description|Force field based on high-energy plasma}}
The '''plasma window''' (not to be confused with a ''plasma shield''<ref>{{cite news| last = Shiga| first =David| title =Plasma bubble could protect astronauts on Mars trip| publisher =[[New Scientist]]| date =2006-07-17| url =https://www.newscientist.com/article/dn9567-plasma-bubble-could-protect-astronauts-on-mars-trip.html| accessdate = 2008-04-02}}</ref>) is a technology that fills a volume of space with [[plasma (physics)|plasma]] confined by a [[magnetic field]]. With current [[technology]], this [[volume]] is quite small and the plasma is generated as a flat [[plane (mathematics)|plane]] inside a [[cylinder (geometry)|cylindrical]] space.

Plasma is any [[gas]] whose [[atom]]s or [[molecule]]s have been [[ionization|ionized]], and is a separate [[phase (matter)|phase]] of matter. This is most commonly achieved by heating the gas to extremely high temperatures, although other methods exist. Plasma becomes increasingly [[viscosity|viscous]] at higher temperatures, to the point where other matter has trouble passing through.

A plasma window's viscosity allows it to separate gas at [[atmospheric pressure#Standard atmosphere|standard atmospheric pressure]] from a total [[vacuum]], and can reportedly withstand a pressure difference of up to nine [[atmosphere (unit)|atmospheres]].<ref>{{cite web|url=https://www.newscientist.com/article/mg17823904.800-hot-mettle.html?full=true |title=Hot mettle |publisher=Newscientist.com |accessdate=2015-05-04}}</ref> At the same time, the plasma window will allow [[radiation]] such as [[laser]] beams and [[charged particle beam|electron beam]]s to pass. This property is the key to the plasma window's usefulness – the technology of the plasma window allows radiation that can only be generated in a vacuum to be applied to objects in an atmosphere.<ref>{{cite news| title = Plasma Window Technology for Propagating Particle Beams and Radiation from Vacuum to Atmosphere| publisher = Nasa Tech Briefs| date =1998-05-01| url =http://www.techbriefs.com/content/view/1834/32/| accessdate = 2008-04-02}}</ref><ref>{{cite news| last = Kaku| first = Michio| title = Physics of the Impossible: A Scientific Exploration into the World of Phasers, Force Fields, Teleportation, and Time Travel| publisher =[[The Wall Street Journal]]| date =2008-03-14| url =https://www.wsj.com/articles/SB120534908289431017?mod=googlenews_wsj| accessdate = 2008-04-02}}</ref> [[Electron-beam welding]] is a major application of plasma windows, making it practical outside a hard vacuum.