Inductively coupled plasma
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2008-06-10T15:21:41Z
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{{otheruses|ICP}}
[[Image:ICP-small.jpg|right|thumb|Picture of an analytical ICP viewed through green [[welder]]'s glass]]
An '''inductively coupled plasma''' ('''ICP''') is a type of [[plasma (physics)|plasma]] source in which the [[energy]] is supplied by [[electrical current]]s which are produced by [[electromagnetic induction]], that is, by time-varying [[magnetic field]]s.<ref>A. Montaser and D. W. Golightly, eds. Inductively Coupled Plasmas in Analytical Atomic Spectrometry, VCH Publishers, Inc., New York, 1992.
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==Operation==
There are two types of ICP geometries: planar and cylindrical. In planar geometry, the electrode is a coil of flat metal wound like a spiral. In cylindrical geometry, it is like a [[helix|helical]] spring.
When a time-varying electric current is passed through the coil, it creates a time varying magnetic field around it, which in turn induces [[azimuthal]] electric currents in the rarefied gas, leading to break down and formation of a plasma. Argon is one example of a commonly used rarefied gas.
Plasma temperatures can range between 6 000 K and 10 000 K, comparable to the surface of the sun.
ICP discharges are of relatively high electron density, on the order of 10<sup>15</sup> cm<sup>-3</sup>.
As a result, ICP discharges have wide applications where a high density plasma is necessary.
Another benefit of ICP discharges is that they are relatively free of contamination because the electrodes are completely outside the reaction chamber. In a [[capacitively coupled plasma]] (CCP), in contrast, the electrodes are often placed inside the reactor and are thus exposed to the plasma and subsequent reactive chemical species.
== Applications ==
* [[ICP-AES]], a type of atomic [[emission spectrometry]]
* [[ICP-MS]], a type of [[mass spectrometry]].
* [[ICP-RIE]], a type of [[reactive ion etching]].
==See also==
*[[Pulsed inductive thruster]]
== References ==
{{reflist}}
== External links ==
* [http://www.cee.vt.edu/ewr/environmental/teach/smprimer/icp/icp.html Inductively Coupled Plasma by Traci Bradford and M. Nicole Cook]
* [http://www.jobinyvon.com/Emission/Principle '''Principle of Atomic Emission''']
[[Category:Electrodynamics]]
[[category:Spectroscopy]]
[[category:Ion source]]
[[category:Plasma physics]]
[[de:Atomspektroskopie#ICP-OES_.28Optische_Emission.29]]
[[fr:Torche à plasma (chimie)]]
[[ja:誘導結合プラズマ]]
[[nl:Inductief gekoppeld plasma]]
[[pt:Espectrometria de Plasma ICP]]
[[ru:Индуктивно-связанная плазма]]