Plasma (physics)

Plasma
Lightning3.jpg NeTube.jpg
Plasma-lamp 2.jpg Space Shuttle Atlantis in the sky on July 21, 2011, to its final landing.jpg
Top: Lightning and neon lights are commonplace generators of plasma. Bottom left: A plasma globe, illustrating some of the more complex plasma phenomena, including filamentation. Bottom right: A plasma trail from the Space Shuttle Atlantis during re-entry into Earth's atmosphere, as seen from the International Space Station.

Plasma (from Ancient Greek πλάσμα, meaning 'moldable substance'[1]) is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir[2] in the 1920s.[3] It consists of a gas of ions – atoms which have some of their orbital electrons removed – and free electrons. Plasma can be artificially generated by heating or subjecting a neutral gas to a strong electromagnetic field to the point where an ionized gaseous substance becomes increasingly electrically conductive. The resulting charged ions and electrons become influenced by long-range electromagnetic fields, making the plasma dynamics more sensitive to these fields than a neutral gas.[4]

Plasma and ionized gases have properties and display behaviours unlike those of the other states, and the transition between them is mostly a matter of nomenclature[2] and subject to interpretation.[5] Based on the temperature and density of the environment that contains a plasma, partially ionized or fully ionized forms of plasma may be produced. Neon signs and lightning are examples of partially ionized plasmas.[6] The Earth's ionosphere is a plasma and the magnetosphere contains plasma in the Earth's surrounding space environment. The interior of the Sun is an example of fully ionized plasma,[7] along with the solar corona[8] and stars.[9]

Positive charges in ions are achieved by stripping away electrons orbiting the atomic nuclei, where the total number of electrons removed is related to either increasing temperature or the local density of other ionized matter. This also can be accompanied by the dissociation of molecular bonds,[10] though this process is distinctly different from chemical processes of ion interactions in liquids or the behaviour of shared ions in metals. The response of plasma to electromagnetic fields is used in many modern technological devices, such as plasma televisions or plasma etching.[11]

Plasma may be the most abundant form of ordinary matter in the universe,[12] although this hypothesis is currently tentative based on the existence and unknown properties of dark matter. Plasma is mostly associated with stars, extending to the rarefied intracluster medium and possibly the intergalactic regions.[13]

History

The word plasma comes from Ancient Greek πλάσμα, meaning 'moldable substance'[1] or 'jelly',[2] and describes the behaviour of the ionized atomic nuclei and the electrons within the surrounding region of the plasma. Very simply, each of these nuclei are suspended in a movable sea of electrons. Plasma was first identified in a Crookes tube, and so described by Sir William Crookes in 1879 (he called it "radiant matter").[14] The nature of this "cathode ray" matter was subsequently identified by British physicist Sir J.J. Thomson in 1897.[15]

The term "plasma" was coined by Irving Langmuir in 1928.[16] Lewi Tonks and Harold Mott-Smith, both of whom worked with Irving Langmuir in the 1920s, recall that Langmuir first used the word "plasma" in analogy with blood.[17][18] Mott-Smith recalls, in particular, that the transport of electrons from thermionic filaments reminded Langmuir of "the way blood plasma carries red and white corpuscles and germs."[19]

Langmuir described the plasma he observed as follows:

"Except near the electrodes, where there are sheaths containing very few electrons, the ionized gas contains ions and electrons in about equal numbers so that the resultant space charge is very small. We shall use the name plasma to describe this region containing balanced charges of ions and electrons."[16]
Other Languages
Afrikaans: Plasma (fisika)
Alemannisch: Plasma (Physik)
aragonés: Plasma (fisica)
অসমীয়া: প্লাজমা
Avañe'ẽ: Plasma
azərbaycanca: Plazma
تۆرکجه: پلاسما
বাংলা: প্লাজমা
Bân-lâm-gú: Tiān-lî-thé
башҡортса: Плазма
беларуская: Плазма
беларуская (тарашкевіца)‎: Плязма
български: Плазма
bosanski: Plazma (fizika)
Чӑвашла: Плазма
čeština: Plazma
dansk: Plasma
eesti: Plasma
Ελληνικά: Πλάσμα (φυσική)
emiliàn e rumagnòl: Plaśma
Esperanto: Plasmo
Fiji Hindi: Plasma
français: État plasma
客家語/Hak-kâ-ngî: Thien-chiông-thí
한국어: 플라스마
hrvatski: Plazma (fizika)
Bahasa Indonesia: Plasma (wujud zat)
interlingua: Plasma (physica)
íslenska: Rafgas
italiano: Plasma (fisica)
ქართული: პლაზმა
қазақша: Плазма
Kreyòl ayisyen: Plasma (fizik)
Кыргызча: Плазма
Latina: Plasma
latviešu: Plazma
лезги: Плазма
lietuvių: Plazma
Limburgs: Plasma
magyar: Plazma
македонски: Плазма
Bahasa Melayu: Plasma (fizik)
Mìng-dĕ̤ng-ngṳ̄: Dēng-liê-cṳ̄-tā̤
မြန်မာဘာသာ: ပလာစမာ (ရူပဗေဒ)
Na Vosa Vakaviti: Plasma
日本語: プラズマ
norsk nynorsk: Plasma
oʻzbekcha/ўзбекча: Plazma
ਪੰਜਾਬੀ: ਪਲਾਜ਼ਮਾ
پنجابی: پلازمہ
Piemontèis: Plasma (fìsica)
polski: Plazma
português: Plasma
română: Plasmă
русский: Плазма
sicilianu: Plasma
Simple English: Plasma (physics)
slovenčina: Plazma (fyzika)
slovenščina: Plazma (fizika)
српски / srpski: Плазма (физика)
srpskohrvatski / српскохрватски: Plazma (fizika)
suomi: Plasma
svenska: Plasma
татарча/tatarça: Plazma
తెలుగు: ప్లాస్మా
Türkçe: Plazma
ئۇيغۇرچە / Uyghurche: پلازما
vepsän kel’: Plazm
Tiếng Việt: Plasma
文言: 電漿
West-Vlams: Plasma
吴语: 等离子体
ייִדיש: פלאזמע
粵語: 電漿
中文: 等离子体