Plasma window 1251318 206733732 2008-04-19T18:30:23Z BOTarate 5870361 robot Adding: [[simple:Plasma window]] The '''plasma window''' (not to be confused with a ''plasma shield''<ref>{{cite news| last = Shiga| first =David| coauthors =| title =Plasma bubble could protect astronauts on Mars trip| work =| pages =| language =| publisher =[[NewScientist]]| date =2006-07-17| url =http://www.newscientistspace.com/article.ns?id=dn9567&feedId=online-news_rss20| 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 [[cylindrical]] space. Plasma is any [[gas]] that has had some of its [[atom]]s or [[molecule]]s [[ionized]] and is generally held to be a separate [[phase (matter)|phase]] of matter. This is most commonly achieved by heating the gas to extremely high temperatures, although other methods also exist. Plasma becomes increasingly [[viscous]] (thick) at higher temperatures, to the point where other matter has trouble passing through. A plasma window's viscosity allows it to separate gas at standard [[atmospheric pressure]] from a total [[vacuum]]. At the same time, the plasma window will allow [[radiation]] such as [[lasers]] and [[Charged particle beam|electron beams]] to pass. This property is the key to the plasma window's usefulness &mdash; the technology of the plasma window permits for radiation that can only be generated in a vacuum to be applied to objects in an atmosphere.<ref>{{cite news| last =| first =| coauthors =| title = Plasma Window Technology for Propagating Particle Beams and Radiation from Vacuum to Atmosphere| work =| pages =| language =| 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| coauthors =| title =Physics of the Impossible: A Scientific Exploration into the World of Phasers, Force Fields, Teleportation, and Time Travel| work =| pages = | language =| publisher =[[The Wall Street Journal]]| date =2008-03-14| url =http://online.wsj.com/article/SB120534908289431017.html?mod=googlenews_wsj| accessdate = 2008-04-02}}</ref> == History == The Plasma Window was invented at [[Brookhaven National Laboratory]]<ref>{{cite news| last =| first =| coauthors =| title =Hot mettle| work =| pages =| language =| publisher =[[NewScientist]]| date =2003-04-12| url =http://www.newscientist.com/article/mg17823904.800-hot-mettle.html| accessdate = 2008-04-02}}</ref> by Ady Hershcovitch and patented in 1995. [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=4&f=G&l=50&co1=AND&d=PTXT&s1=Hershcovitch.INNM.&OS=IN/Hershcovitch&RS=IN/Hershcovitch] Further inventions using this principle include the Plasma Valve in 1996. [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=17&f=G&l=50&co1=AND&d=PTXT&s1=plasm&s2=window&OS=plasm+AND+window&RS=plasm+AND+window] == Plasma Valve == A related technology is the <!-- [[plasma valve]] relink if separate article has been created-->plasma valve, invented shortly after the plasma window. A plasma valve is a layer of gas in the shell of a [[particle accelerator]]. The ring of a particle accelerator contains a vacuum, and ordinarily a breach of this vacuum is disastrous. If, however, an accelerator equipped with plasma valve technology breaches, the gas layer is ionized within a nanosecond, creating a seal that prevents the accelerator's decompression. This gives researchers time to shut off the particle beam in the accelerator and slowly decompress the accelerator ring to avoid damage. == Properties == The physical properties of the plasma window vary depending on application, but so far most have been generated at temperatures around 15,000 [[Kelvin]] ({{US patent|5578831}}) The only limit to the size of the plasma window are current energy limitations as generating the window consumes around 20 kW per inch (8 kW/cm) in the diameter of a round window. The plasma window emits a bright glow, with the color being dependent on the gas used. == Similarity to "force fields" == In [[science fiction]], such as the [[television]] series ''[[Star Trek]]'', a fictional technology known as the "[[force field (science fiction)|force field]]" is often used as a device. In some cases it is used as an external "door" to [[hangar|hangars]] on [[space ships]], in order to prevent the ship's internal [[atmosphere]] from venting into [[outer space]]. Plasma windows could theoretically serve such a purpose if enough energy were available to produce them.<ref>{{cite news| last =Marshall| first =Michael| coauthors =| title =10 impossibilities conquered by science| work =| pages =| language =| publisher =[[NewScientist]]| date =2008-04-03| url =http://technology.newscientist.com/channel/tech/dn13556-10-impossibilities-conquered-by-science.html| accessdate = 2008-04-03}}</ref> == External links == *[http://www.nasatech.com/Briefs/May98/0598ETB1.html Official article by Ady Hershcovitch] - Inventor of the Plasma Window. *[http://www.bnl.gov/bnlweb/pubaf/pr/1996/bnlpr080896.html BROOKHAVEN LAB WINS R&D 100 AWARD FOR THE "PLASMA WINDOW"] *[http://www.bnl.gov/world/ Brookhaven National Laboratory] - Where the Plasma Window was invented *[http://www.bnl.gov/bnlweb/pubaf/pr/2001/bnlpr121101b.htm News on the Plasma Window] *{{US patent|5578831|Plasma Window Patent}} *[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/search-bool.html&r=9&f=G&l=50&co1=OR&d=ptxt&s1='Plasma+Window'&s2='Ady+Hershcovitch'&OS=%22Plasma+Window%22+OR+%22Ady+Hershcovitch%22&RS=%22Plasma+Window%22+OR+%22Ady+Hershcovitch%22 Plasma Valve Patent] == References == {{reflist}} *Ady Hershcovitch (1995). High-pressure arcs as vacuum-atmosphere interface and plasma lens for nonvacuum [[electron beam welding]] machines, electron beam melting, and nonvacuum ion material modification, ''Journal of Applied Physics'', 78(9): 5283-5288 * BNL Wins R&D 100 Award for `Plasma Window' [http://www.bnl.gov/bnlweb/pubaf/bulletin/1996/bb101896.pdf] *Ady Hershcovitch. Plasma Window Technology for Propagating Particle Beams and Radiation from Vacuum to Atmosphere. [http://www.nasatech.com/Briefs/May98/0598ETB1.html] [[Category:Plasma physics]] [[he:חלון פלזמה]] [[simple:Plasma window]]