Plasma globe: Difference between revisions

Revision as of 01:11, 20 December 2006

Latest revision as of 05:23, 26 July 2025

(999 intermediate revisions by more than 100 users not shown)

Line 1:

{{Short description|Decorative electrical device}}

{{unreferenced|date=October 2006}}

{{Distinguish|Plasma lamp}}

[[Image:Plasma-lamp 2.jpg|thumb|180px|right|A plasma lamp]]

{{refimprove|date = January 2016}}

[[Image:Plasma lamp touching.jpg|right|180px|thumb|The effect of a conducting object (such as a hand) in close proximity to the plasma globe glass]]

[[File:Plasma globe 60th.jpg|thumb|A plasma ball with filaments extending between the inner and outer spheres]]

A '''plasma ball''', '''plasma globe''', or '''plasma lamp''' is a clear glass container filled with [[noble gas]]es, usually a mixture of [[neon]], [[krypton]], and [[xenon]], that has a [[high-voltage]] [[electrode]] in the center of the container. When voltage is applied, a [[plasma (physics)|plasma]] is formed within the container. [[Plasma (physics)#Filamentation|Plasma filaments]] extend from the inner electrode to the outer glass insulator, giving the appearance of multiple constant beams of colored light. Plasma balls were popular as [[novelty item]]s in the 1980s.<ref name=Gache/>

The [[plasma lamp]] was invented by [[Nikola Tesla]], during his experimentation with high-frequency [[electric current|currents]] in an evacuated glass [[vacuum tube|tube]] for the purpose of studying [[high voltage]] phenomena.<ref name=pbs>{{cite web |url=https://www.pbs.org/tesla/res/res_art05.html |title=Experiments with Alternate Currents of High Potential and High Frequency |first=Nikola |last=Tesla |website=[[PBS]] |year=1892 |access-date=July 26, 2010 |url-status=live |archive-url=https://web.archive.org/web/20100302125234/http://www.pbs.org/tesla/res/res_art05.html |archive-date=March 2, 2010 }}</ref> Tesla called his invention an "[[inert gas]] [[Gas discharge tube|discharge tube]]".<ref name=powerlabs>{{cite web |url=http://www.powerlabs.org/plasmaglobes.htm#%C2%A0PRINCIPLE%20OF%20OPERATION: |title=PowerLabs Plasma Globes Page |first=Sam |last=Barros |year=2002 |access-date=November 16, 2009 <!-- section=Principle of operation --> |url-status=live |archive-url=https://web.archive.org/web/20091203054631/http://www.powerlabs.org/plasmaglobes.htm#%C2%A0PRINCIPLE%20OF%20OPERATION: |archive-date=December 3, 2009 }}</ref> The modern plasma lamp design was developed by [[James Falk]] and MIT student [[Bill Parker (MIT)|Bill Parker]].<ref name=Gache>{{cite web |url=http://news.softpedia.com/news/How-do-Plasma-Lamps-Work-77633.shtml |title=How do plasma lamps work? |first=Gabriel |last=Gache |date=January 31, 2008 |website=Softpedia |access-date=November 16, 2009 |url-status=live |archive-url=https://web.archive.org/web/20090210232935/http://news.softpedia.com/news/How-do-Plasma-Lamps-Work-77633.shtml |archive-date=February 10, 2009 }}</ref><ref>{{cite web |url=https://www.technologyreview.com/2023/10/24/1081096/making-the-invisible-visible/ |title=MIT News: Alumni profile - Making the invisible visible - Bill Parker '74, SM '93 |author=Ken Shulman |date=October 24, 2023}}</ref>

[[image:Photos-photos 1087592507 Energy Arc.jpg|180px|right|thumb|The central electrode of a plasma globe]]

'''Plasma lamps''' (also variously [[plasma (physics)|plasma]] globes, balls, domes, spheres, or orbs) are [[novelty item]]s which were most popular in the [[1980s]]. The plasma lamp was invented by [[Nikola Tesla]] after his experimentation with high frequency [[electric current|currents]] in an evacuated glass [[vacuum tube|tube]] for the purpose of studying [[high voltage]] phenomena. Tesla called this invention an ''[[inert gas|Inert Gas]] Discharge Tube''.

A [[crackle tube]] is a related device filled with phosphor-coated beads.

'''Plasma''' is a highly ionized gas consisting of almost equal numbers of free electrons and positive ions.

== Construction ==

This is so dumb, plasma is strange.

Although many variations exist, a plasma ball is usually a clear glass sphere filled with a mixture of various gases (most commonly [[neon]], sometimes with other [[noble gas]]es such as [[argon]], [[xenon]] and [[krypton]]) at nearly atmospheric pressure.

==Description==

Plasma lamps are available in different shapes, including spheres and cylinders. Although there are many variations, a plasma lamp is usually a clear glass orb, filled with a mixture of various gases at low pressure, and driven by high frequency [[alternating current]] at high voltage (approx. 35[[Hertz|kHz]], 2-5[[volt|kV]]), generated by a high voltage [[transformer]]. A much smaller orb in its center serves as an [[electrode]]. Beams or snakes of "light" (actually [[emergence|emergent patterns]] in [[ion]]ized gas) extend from the inner electrode to the outer glass container, giving an appearance similar to multiple constant beams of coloured lightning (see [[corona discharge]] and [[electric glow discharge]]). The beams first follow the electric field lines of the [[dipole]], but move up due to [[convection]].

Plasma balls are driven by high-frequency (approximately {{nowrap|35 [[hertz|kHz]]}}) [[alternating current]] at {{nowrap|2–5 [[volt|kV]]}}.<ref name=Gache/> The drive circuit is essentially a specialized [[power inverter]], in which current from a lower-voltage DC supply powers a high-frequency [[electronic oscillator]] circuit whose output is stepped up by a high-frequency, high-voltage [[transformer]], for example a miniature [[Tesla coil]] or a [[flyback transformer]]. The radio-frequency energy from the transformer is transmitted into the gas within the ball through an electrode at its center. Additionally, some designs utilize the ball as a resonant cavity, which provides positive feedback to the drive transistor through the transformer. A much smaller hollow glass orb can also serve as an [[electrode]] when it is filled with metal wool or a conducting fluid that is in communication with the transformer output. In this case, the radio-frequency energy is admitted into the larger space by [[capacitive coupling]] right through the glass. [[Plasma (physics)|Plasma]] filaments extend from the inner electrode to the outer glass insulator, giving the appearance of moving tendrils of colored light within the volume of the ball {{Crossreference|(see [[corona discharge]] and [[electric glow discharge]])}}. If a hand is placed close to the ball it produces a faint smell of [[ozone]], as the gas is produced by high voltage interaction with atmospheric oxygen.

Placing a hand near the glass alters the high-frequency [[electric field]], causing a single beam to migrate from the inner ball to the point of contact. An electric current is produced within any conductive object near the orb, as the glass doesn't block the flow of [[current (electricity)|current]] when high [[frequency|frequencies]] are involved; the glass acts as the [[dielectric]] in a [[capacitor]] formed between the ionized gas and the hand.

Some balls have a control knob that varies the amount of power going to the center electrode. At the very lowest setting that will light or "strike" the ball, a single tendril is made. This single tendril's plasma channel engages enough space to transmit this lowest striking energy to the outside world through the glass of the ball. As the power is increased, this single channel's capacity is overwhelmed and a second channel forms, then a third, and so on. The tendrils each compete for a footprint on the inner orb as well. The energies flowing through these are all of the same polarity, so they repel each other as like charges: a thin dark boundary surrounds each footprint on the inner electrode.

One should be careful when placing electronic devices (such as a computer mouse) nearby or upon the plasma lamp: not only may the glass become hot, but the high voltage may place a substantial [[electric charge|static charge]] into the device, even through a protective plastic casing. The [[radio frequency]] field produced by plasma lamps can interfere with the operation of [[touchpad]]s used on [[laptop computer]]s, [[digital audio player]]s, and other similar devices. Additionally, when a metal is placed on the surface of a plasma lamp's glass, a danger of shock and burning does exist; it is very easy for electricity to be emitted from the lamp if said metal comes in contact or close proximity with certain other materials, including human tissue.

The ball is prepared by pumping out as much air as is practical. The ball is then backfilled with neon to a pressure similar to one atmosphere. If the radio-frequency power is turned on, if the ball is "struck" or "lit", now, the whole ball will glow a diffuse red. If a little argon is added, the filaments will form. If a very small amount of xenon is added, the "flowers" will bloom at the ends of the filaments.{{citation needed|date=November 2012}}

[[Ozone]] may also accumulate near the surface of the glass orb after a few minutes of constant operation. It accumulates at an accelerated rate if a hand or metal object is placed on the glass.

The neon available for purchase for a neon-sign shop often comes in glass flasks at the pressure of a partial vacuum. These cannot be used to fill a ball with a useful mixture. Tanks of gas, each with its specific, proper, pressure regulator and fitting, are required: one for each of the gases involved.

Of the other noble gases, [[radon]] is [[radioactive]], [[helium]] escapes through the glass relatively quickly, and [[krypton]] is expensive. Other gases such as [[Mercury (element)|mercury]] vapor can be used. Molecular gases may be dissociated by the plasma.

== Interaction ==

[[File:Plasma lamp touching.jpg|thumb|The effect of a conducting object (a hand) touching the plasma ball]]

Placing a finger tip on the glass creates an attractive spot for the energy to flow because the conductive human body (having an internal resistance less than 1000 ohms)<ref>{{cite journal |journal=ePlasty |date=12 Oct 2009 |volume=9 |page=e44 |pmc=2763825 |pmid=19907637 |title=Conduction of Electrical Current to and Through the Human Body: A Review |first1=Raymond M. |last1=Fish |first2=Leslie A. |last2=Geddes}}</ref> is more easily polarized than the dielectric material around the electrode (i.e. the gas within the ball) providing an alternative discharge path having less resistance. Therefore, the capacity of the large conducting body to accept radio frequency energy is greater than that of the surrounding air. The energy available to the filaments of plasma within the ball will preferentially flow toward the better acceptor. This flow also causes a single filament, from the inner ball to the point of contact, to become brighter and thinner.<ref name=Gache/> The filament is brighter because there is more current flowing through it and into the human body, which has a [[capacitance]] of about 100&nbsp;pF.<ref>{{cite journal |journal=Journal of Chiropractic Medicine |date=Dec 2014 |volume=13 |issue=4 |pages=239–246 |doi=10.1016/j.jcm.2014.10.001 |title=Analysis of the Charge Exchange Between the Human Body and Ground: Evaluation of "Earthing" From an Electrical Perspective |first1=Kent |last1=Chamberlin |first2=Wayne |last2=Smith |first3=Christopher |last3=Chirgwin |first4=Seshank |last4=Appasani |first5=Paul |last5=Rioux |pmid=25435837 |pmc=4241473 }}</ref> The filament is thinner because the magnetic fields around it, augmented by the now-higher current flowing through it, cause a [[Magnetohydrodynamics|magnetohydrodynamic effect]] called [[Pinch (plasma physics)|pinch]]: the plasma channel's own magnetic fields create a force acting to compress the size of the plasma channel itself.

[[File:WLANL - petertf - Teslabol.jpg|thumb|left|A "Tesla ball" at the [[NEMO (museum)|NEMO science museum]] in Amsterdam]]

Much of the movement of the filaments is due to heating of the gas around the filament. When gas along the filament is heated, it becomes more buoyant and rises, carrying the filament with it. If the filament is discharging into a fixed object (like a hand) on the side of the ball, it will begin to deform into a curved path between the central electrode and the object. When the distance between the electrode and the object becomes too great to maintain, the filament will break and a new filament will reform between the electrode and the hand {{Crossreference|(see also [[High voltage traveling arc#Visual entertainment|Jacob's Ladder]], which exhibits a similar behavior)}}.

An electric current is produced within any conductive object near the orb. The glass acts as a [[dielectric]] in a [[capacitor]] formed between the ionized gas and the hand.

{{breakafterimages}}

== Gallery ==

By adjusting the voltage, frequency, chemical composition and pressure of gas in the globe, many colorful effects can be achieved

{{gallery |height=120 |width= |mode=packed |align=center |header= |footer=

|File:Plasma-lamp 3.jpg|

|File:上海科技馆1楼 - panoramio.jpg|

|File:L3180767 plasma ball kula plazmowa.jpg|

|53 Barcelona CosmoCaixa 02082016.jpg|

|File:Glass plasma globe.jpg|

|File:Plasma lamp bulb.svg|

|File:Plasma02.jpg|

|File:Шар Тесла.jpg|

|File:Plasmalampe.JPG|

}}

==History==

[[File:Plasma globe 23s.webm|thumb|Video of plasma ball]]

In {{US patent|0514170}} ("''Incandescent Electric Light''", 1894 February 6), [[Nikola Tesla]] describes a plasma lamp. This patent is for one of the first high intensity discharge lamps. Tesla took an incandescent type lamp globe with the suspended conductive element and excited the element with high voltage currents from a [[Tesla coil]], thus creating the brush discharge emanation. He gains patent protection on the particular forms of the lamp in which a light giving small body or button of refractatory material is supported by a conductor entering a very highly exhausted globe or receiver. Tesla later called this invention an "Inert Gas Discharge Tube".

In {{US patent|0514170}} ("Incandescent Electric Light", 1894 February 6), [[Nikola Tesla]] describes a plasma lamp. This patent is for one of the first high-intensity discharge lamps. Tesla used an incandescent-type lamp ball with a single internal conductive element and excited the element with high voltage currents from a [[Tesla coil]], thus creating the brush discharge emanation. He gained patent protection on a particular form of the lamp in which a light-giving small body or button of refractory material is supported by a conductor entering a very highly exhausted ball or receiver. Tesla called this invention the single terminal lamp, or, later, the "Inert Gas Discharge Tube".<ref name=powerlabs/>

The Groundstar style of plasma ball was created by [[James Falk]] and marketed to collectors and science museums in the 1970s and 1980s.<ref name=Gache/> [[Jerry Pournelle]] in 1984 praised Orb Corporation's Omnisphere as "the most fabulous object in the entire world" and "magnificent ... a new kind of art object", stating "you can't buy mine for any price".<ref name="pournelle198404">{{cite news | url=https://archive.org/stream/byte-magazine-1984-04/1984_04_BYTE_09-04_Real-World_Interfacing#page/n57/mode/2up | title=The Most Fabulous Object in the Entire World | work=BYTE | date=April 1984 | access-date=2 March 2016 | author=Pournelle, Jerry | pages=57 | url-status=live | archive-url=https://web.archive.org/web/20160325205606/https://archive.org/stream/byte-magazine-1984-04/1984_04_BYTE_09-04_Real-World_Interfacing#page/n57/mode/2up | archive-date=25 March 2016 }}</ref>

The popular product sold throughout the world today was invented by the artist [[Bill Parker (MIT)|Bill Parker]], while an undergraduate student at [[Massachusetts Institute of Technology|MIT]]. Later he developed it into the now ubiquitous product while he was an Artist in Residence at the [[Exploratorium]] science museum. The technology needed to carefully formulate gas mixtures used in today's plasma spheres, primarily combinations of high purity rare gases, was not available to Tesla. These gas mixtures, glass shapes and integrated circuit driven electronics used to create the vivid colors, range of motions and complex patterns seen in today's plasma spheres were all developed and patented by Bill Parker in the 1980s and 1990s. The lamps typically contain [[xenon]], [[krypton]] and/or [[neon]], though a number of other gases can be used as well.

The technology needed to formulate gas mixtures used in today's plasma spheres was not available to Tesla.{{Citation needed|date=February 2010}} Modern lamps typically use combinations of [[xenon]], [[krypton]] and [[neon]], although other gases can be used.<ref name=Gache/><ref name=powerlabs/> These gas mixtures, along with different glass shapes and integrated-circuit-driven electronics, create the vivid colors, range of motions, and complex patterns seen in today's plasma spheres.

==Applications==

Plasma lampsballs are mainly used as curiosities or toys for their unique lighting effects and the '"tricks'" that can be performed on them by users moving thetheir hands around them. They might also form part of a school's laboratory equipment for demonstration purposes. They are not usually employed for general lighting. However, in recent years, some novelty stores have begun selling miniature plasma ball [[nightlight]]s that can be mounted on a standard light socket.<ref>[https://gizmodo.com/327065/plasma-ball-night-light-makes-us-nostalgic-for-bed-wetting Plasma Ball Night Light Makes Us Nostalgic For Bed Wetting] {{webarchive|url=https://web.archive.org/web/20170908155122/https://gizmodo.com/327065/plasma-ball-night-light-makes-us-nostalgic-for-bed-wetting |date=2017-09-08 }}, gizmodo.com, 2007-11-27</ref><ref>[http://www.4physics.com/catalog/product_info.php/cPath/28/products_id/364 Plasma Night Light] {{webarchive|url=https://web.archive.org/web/20101201083238/http://www.4physics.com/catalog/product_info.php/cPath/28/products_id/364 |date=2010-12-01 }}, 4physics.com, 2010-02-17</ref>

Plasma balls can be used for experimenting with [[high voltage]]s. If a conductive plate or wire coil is placed on the ball, [[capacitive coupling]] can transfer enough voltage to the plate or coil to produce a small [[electric arc|arc]] or energize a high voltage [[electrical load|load]]. This is possible because the plasma inside the ball and the conductor outside it act as plates of a capacitor, with the glass in between as a dielectric. A step-down transformer connected between the plate and the ball's electrode can produce lower-voltage, higher-current radio frequency output. Careful earth grounding is essential to prevent injury or damage to equipment.

==Uses in popular culture==

In addition, plasma balls and their variations have been employed as props and sources for special effects for [[science fiction]] [[television show]]s. Among the first appearances was a plasma ball's light output, with the glass envelope filtered out, depicting the alien [[Chocky]] in the 1984 science fiction series of the same name. In March 1985, was a plasma ball featured as the aliens "Doomsday Weapon" on the TV sci-fi series ''[[V (TV series)|V: The Series]]'' episode "War of Illusions". A plasma ball or "gizmo" was part of the primary plot as the time- and space-warping engine of an alien spacecraft in the 1985 science fiction movie ''[[My Science Project]]'' released in August 1985. Commercially-available units (lightning plates) are prominently depicted as part of [[Borg (fictional aliens)|Borg]] technology in the series ''[[Star Trek: The Next Generation]]''. Plasma balls also feature in the opening sequences of ''[[The X-Files]]''. The [[Futurama]] episode ''[[Insane in the Mainframe]]'' features a robot with a plasma lamp for a head.

==Hazards==

In the UK, the late Kenny Everett, had a plasma ball in front of him when he presented a television science quiz programme for the [[BBC]]. The programme was not particularly successful and did not last more than one series.

Bringing conductive materials or electronic devices close to a plasma ball may cause the glass to become hot. The high voltage radio frequency energy coupled to them from within the ball may cause a mild electric shock to the person touching, even through a protective glass casing. The [[radio frequency]] field produced by plasma balls can interfere with the operation of touchpads used on [[laptop computer]]s, [[digital audio player]]s, [[cell phones]], and other similar devices.<ref name=Gache/> Some types of plasma ball can radiate sufficient [[radio frequency interference]] (RFI) to interfere with [[cordless telephone]]s and [[Wi-Fi]] devices several feet or some meters away.

If an electrical conductor touches the outside of the ball, [[capacitive coupling]] can induce enough potential on it to produce a small [[electric arc|arc]]. This is possible because the ball's glass acts as a capacitor [[dielectric]]: the inside of the lamp acts as one plate, and the conductive object on the outside acts as the opposite capacitor plate.<ref name=powerlabs/> This is a dangerous action that can damage the ball or other electronic devices, and presents a fire ignition hazard.<ref name=Gache/>

==See also==

{{Commons|Plasma lamp}}

*[[Fusor]]

*[[Lava lamp]]

*[[Plasma (physics)]]

*[[List of light sources]]

Perceptible amounts of [[ozone]] can be formed on the surface of a plasma ball. Many people can detect ozone at concentrations of {{val|0.01|-|0.1|ul=ppm}}, which is right below the lowest concentration at which ozone is considered harmful to health. Exposure of {{val|0.1|to|1|ul=ppm}} produces headaches, burning eyes, and irritation to the respiratory passages.

==External links==

*[http://www.powerlabs.org/plasmaglobes.htm#%A0PROFESSIONAL%20PLASMA%20GLOBES: POWERLABS.org &mdash; Plasma Globes]

*[http://amasci.com/tesla/heli1.html Science Hobbyist: Plasma globes without glass or vacuum]

*[http://fhqed.free.fr/plasma/plasma.htm See a plasma lamp in action ! (Videos and pictures)]

*[http://www.geocities.com/delacroix101/ Detailed plan to building your own plasma globe]

*[http://www.esnips.com/web/Plasma-Art Plasma Art]

In July 2022, a spark from a plasma globe at the ''[[Questacon]]'' museum in Australia ignited the alcohol-based hand sanitiser that had been applied to a child's hands leaving them with serious burns.<ref>{{cite news |last=Twyford |first=Lottie |date=2024-08-07 |title=Federal government department charged after nine-year-old child's hands allegedly caught fire while touching plasma globe at Questacon |url=https://www.abc.net.au/news/2024-08-07/department-charged-after-child-hands-caught-fire-at-questacon/104194556 |work=[[ABC News (Australia)|ABC News]] |___location=[[Canberra]] |access-date=2024-08-07}}</ref>

==See also==

{{Commons|Plasma lamp}}

* [[Fusor]]

* [[List of light sources]]

* [[Sulfur lamp]]

* [[Vacuum arc]]

== References ==

{{ArtificialLightSources}}

{{Reflist|30em}}

{{Nikola Tesla}}

[[Category:Lamps]]

{{Artificial light sources}}

[[Category:Plasma physics]]

{{Portal bar|1980s|Electronics}}

[[Category:Nikola Tesla]]

[[Category:1980s fads and trends]]

[[de:Plasmalampe]]

[[Category:Articles containing video clips]]

[[es:Lámpara de plasma]]

[[Category:Gas discharge lamps]]

[[fr:Lampe à plasma]]

[[Category:Inventions by Nikola Tesla]]

[[ko:플라스마 램프]]

[[idCategory:LampuNovelty plasmaitems]]

[[Category:Plasma technology and applications]]

[[pl:Kula plazmowa]]

[[ru:Плазменная лампа]]

[[fi:Plasmapallo]]