Talk:Plasma (physics)

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Unfortunately I can't edit this page myself. Too bad, but I hope someone will read this and do the correction.

In the "common forms of plasma" we have "Some extremely hot flames [citation needed]".

First of all - the citation can be found in the "flames" article: [1]

Secondly, that citation doesn't claim that only "extremely hot flames" are plasma, but rather that ALL flames are plasma, including the flame of a candle: "What about fire? The flame of a burning candle is ionized, as we now know, and thus a plasma". So the article should be corrected by replacing "Some extremely hot flames" with "The flames of a fire (even candles)". (talk) 10:38, 27 May 2012 (UTC)

  1. ^ Verheest, Frank (2000). "Plasmas as the fourth state of matter". Waves in Dusty Space Plasmas. Norwell MA: Kluwer Academic. p. 1. ISBN 0-7923-6232-2. 
I agree that this should be fixed. There's a nice YouTube video called "Electric Flame" (linking to youtube is so complicated). It demonstrates that flames contain ions. Tadmuck (talk) 19:10, 2 March 2013 (UTC)

State of matter[edit]

I didn't see any citation for plasma being a forth state of matter. I came here looking for evidence of it but all I could find was a table that seems to be trying to show that it is a 4th state but it's not very convincing. Specific question I am left with: If gases become plasmas when they are ionized, why do liquids not have a separate state of matter when they are ionized? Calling plasma a separate state of matter seems premature since they are apparently still being heavily researched and it also seems like something self-important physicists would claim, hence why I am looking for the actual citations.

Also, why is this article restricted to (physics)? shouldn't it also have a (chemistry) entry or preferably none of these parentheses at all? esp. given its status as 4th state of matter it would be of interest to students of chemistry69.223.177.179 (talk) 23:24, 16 January 2012 (UTC)

"State of matter" is not such a well-defined concept that everyone agrees on what is or isn't a separate state, and consequently it isn't of central importance to the physical sciences. There is a disambiguation article on Plasma, without parentheses, but chemists will be interested in the same definition of plasma as physicists. Art Carlson (talk) 07:51, 17 January 2012 (UTC)

It's really considered to be "common knowledge" that plasma is considered to be a fourth state of matter.  ;) — Preceding unsigned comment added by (talk) 01:11, 16 June 2012 (UTC)

And should be considered the "First" state of matter, not the fourth - since even in Big Bang cosmology the first state of matter was plasma. So shouldn't we call it what we really believe it to be? Steven J White (talk) 13:48, 9 November 2014 (UTC)

Removed ball lightning[edit]

I have removed ball lightning because the page linked doesn't even say what it is, so we can't say it is plasma. From the page: Ball lightning is an unexplained atmospheric electrical phenomenon. The term refers to reports of luminous, usually spherical objects which vary from pea-sized to several metres in diameter. It is usually associated with thunderstorms, but lasts considerably longer than the split-second flash of a lightning bolt. Many of the early reports say that the ball eventually explodes, sometimes with fatal consequences, leaving behind the odour of sulfur. [23 May 2006] Iæfai (talk) 02:52, 19 March 2012 (UTC)

You should put it back, being as we know it is an atmospheric electrical phenomenon - and only plasma's are highly electrically conductive in gaseous states. Steven J White (talk) 13:53, 9 November 2014 (UTC)

Definition in Introduction[edit]

Not to nitpick but since this is a physics-related topic and a certain amount of "rigor" might be expected, I wonder if it might be more appropriate to say that plasma is a *kind* of matter, or *form* of matter; rather than a "state of matter." After all, plasma is an actual "physical substance" with mass, electrical charge, etc., it's not just a state, it's the actual matter itself. "State of matter" implies that Plasma = state - - but Plasma *is* matter. I only mention it since, like I said, it's a physics-related article and a certain amount of "rigor" might be appropriate.

I think "state of matter" is more appropriate, similar to its use when describing solids, liquids and gases. They could also be argued to be "kinds" or "types" of matter, but we are describing the state of matter here. --Iantresman (talk) 22:34, 8 November 2012 (UTC)

Yet in cosmological theory, plasma was the first state of matter to exist - and 99% of the universe "still" exists in this state. Still has not condensed into states of matter that have equal numbers of protons and electrons - solids, liquids and gasses - to which it behaves nothing like. It is the most unique "state" of matter there is, to which nothing else can be compared.. Steven J White (talk) 13:56, 9 November 2014 (UTC)

Comparison to the gas phase[edit]

In the section "Comparison of plasma and gas phases", the text reads that plasma ".. is closely related to the gas phase in that it also has no definite form or volume".

One of the characteristics of plasmas, is that it may indeed have both definite form and volume, eg. filamentation, the stars, heliospheric current sheet, etc. Should we reword, or find a different similarity? --Iantresman (talk) 22:59, 8 November 2012 (UTC)

I agree, which is why I protested when they took out the part about it having a behavior uniquely different from gas. Plasma (highly charged matter) has nothing in common with "neutral matter." We don't even use the same physics to describe each one. Steven J White (talk) 15:08, 20 February 2015 (UTC)

What about the CRT[edit]

Does a cathode ray tube, or for that matter, any vacuum tube have a plasma? I like to saw logs! (talk) 06:17, 30 January 2013 (UTC) according to deffinition, yes. it is ionized gas-- (talk) 17:28, 30 April 2013 (UTC)

'...Even black holes' (disapprove of this description)[edit]

Even black holes, which are not directly visible, are fuelled by accreting ionising matter. This is a weird assertion; that black holes are 'fuelled'. I cannot find any support for that idea in the reference either. (talk) 06:39, 21 April 2013 (UTC) BGriffin

Because they are Z-Pinches in a universe 99% plasma. [1] [2]

Simply charged particles orbiting a common electromagnetic center - not particles orbiting a point object of zero volume. See 2:23 timeline in the following. Steven J White (talk) 15:09, 20 February 2015 (UTC)

Steven, If you think you see a way to improve the article, then please improve it. Isambard Kingdom (talk) 15:24, 20 February 2015 (UTC)

secondary plasma field[edit]

when a secondary plasma field is generated by the interactions of certain metals and the primary plasma field ,a wide variety of observable phenomenon,may be viewed.finer metals and meshes work the best as hard or dense metals absorb to much themselves. the particular interaction between steelwool and stainless steel and the secondary field should be done under controlled conditions, as the steel wool will combust. the interaction with carbon to absorb ,ie your radio station signal within a reasonable distance to secondary field 12 feet or more. a third plasma reaction with yet a third gas will definitely bring more interesting observation. Ronald sykes (talk) 05:51, 13 July 2013 (UTC)

plasma field interaction to create motion[edit]

With the use of a simple glass plasma globe,filled with various gasses,and the interaction with a non magnetic stainless steel mesh,wrapped over said globe, the interaction with the cosmic fields around us and outside earths vacume can be observed. with the use of common diodes and some newer materials ie. the new dimmer switches ,paired, a dual high voltage generator, a secondary evacuated gas tube,a 1 to 1 induction transformer and various arangements of capacitors,diodes and resistors, to create a varying field . this varying field effect will interact with a magnetic field,causing a varying flux, creating an observable up and down motion, if components are poised properly.although plasma interaction with the stainless steel requires a source of negative ions to perform the said function,this problem can easily be solved either by holding the ground source your self,as the human body is a type of plasma,the use of a ground wire to earth, or another source of non magnetic stainless steel.Ronald sykes (talk) 22:52, 21 July 2013 (UTC)

Nuclear Pasta[edit]

There are 5 states of matter now, another Pluto incident. Drrake (talk) 03:49, 24 July 2013 (UTC)


The article refers to the electrons in a plasma as not actually being "free":

"It is important to note that although they are unbound, these particles are not ‘free’."

But the electrons are later referenced as "free electrons" here:

"The term "plasma density" by itself usually refers to the "electron density", that is, the number of free electrons per unit volume."

Would "unbound" not be a better term? Ducksandwich (talk) 15:17, 4 November 2013 (UTC)

A Conditions of Plasma[edit]

→Why debye length should be less than plasma length?(ZK)Plasma group please answere..'— Preceding unsigned comment added by Zikizk (talkcontribs) 10:23, 10 February 2014 (UTC)

Heat transfer[edit]

(ZK) Added image description from the potentials section to heat transfer, here. Prokaryotes (talk) 21:09, 5 April 2014 (UTC)

Disputed - "Plasma is the most abundant form of matter in the Universe, because most stars are in a plasma state."[edit]

I was going to add a disputed tag, but I'll just post it in the talk page first and add it if I get no responses here. This statement says it is the most abundant form of matter, but I'm pretty sure that title goes to "dark matter" or "dark energy," which while not characterized well in physics, has for more mass in this universe than regular matter we can see. Since we can only see it's effects on regular matter it may have been discounted. Maybe a qualifier should be added, like excluding dark matter and energy, or "regular matter," unless there is a more suitable term. If you disagree let me know why it should be called the most abundant form of matter.Wgfcrafty (talk) 07:22, 24 June 2014 (UTC)

Multipole resonance probe[edit]

The wiki needs a new article about the multipole resonance probe, developed by a group of scientists at the Ruhr University in Bochum Germany. It is a new diagnostic approach for plasma measurement. (talk) 15:34, 6 November 2014 (UTC)

Meaning of "definition"[edit]

In section 1.1 it states:

A definition can have three criteria:

Does this mean that the following three "criteria" must be met for the system to be called plasma? If so, this should be stated directly.

Note also that the three "criteria" are not binary tests (the usual meaning of criterion), but ratios that must come out large in order for it to be considered a plasma (assuming this is the intention). Then being a plasma is a matter of degree, and this should be reflected in the language chosen. (talk) 09:11, 8 November 2014 (UTC)

Plasma parameter[edit]

I flagged the phrase "plasma parameter" in two places. It is used in two different senses - in the first case as the particular ratio Λ, in the second as any of several numbers. (talk) 09:11, 8 November 2014 (UTC)

US or British spelling?[edit]


Actually, it wasn't. The first version appears to use British English[1]. The clue is the spelling of "behaviour".

I only raise this because a recent revert [2] seems a bit picky? Aarghdvaark (talk) 03:05, 9 December 2014 (UTC)

Wording question[edit]

Under the heading Thermal vs. Non-Thermal Plasmas, there is a sentence: "Non-thermal plasmas on the other hand have the ions and neutrals at a much lower temperature..."

I don't think "neutrals" is correct. However, I don't know if the intended word was "neutrons" or "neclei." Kirby777 (talk) 21:58, 24 May 2015 (UTC)Kirby777, 5-24-15 at 5:00 pm CST.

Chemist begs to differ, apart from much clearer, further substantiation[edit]

I have read here, and elsewhere at WP, that it is common knowledge that plasmas are a forth state of matter, alongside s-l-g. Like an earlier reader, I reply that the article does not make this clear, from a scholarly perspective—I do not see the substantiation, that there is acceptance, broadly, across the relevant fields—which include chemistry of all stripes—that plasmas should be considered and taught as a fourth state.

Perhaps differences between my and others asking this before me are that I am a chemical professional, active in research, teaching, and writing, and that I see the following, seemingly clear conundrum:

If the heating, EM field, laser, or microwave perturbation required to create a plasma "decreases or increases the number of electrons, creating... ions"... [a process] that "is accompanied by the dissociation of molecular bonds present"[ref name="Sturrock"]… [emphasis added], then this is not a physical change of state at all, but rather a clear chemical reaction whose atomized products present very unique and seemingly (cosmically) very important physical properties. Illustrate it generally how you will, promote it how you will, there is no plasma state of aspirin, and converting aspirin to a CHO plasma is not a physical change of the state of this matter—though the same 2-(acetoxy)benzoic acid does enter the liquid state at 135°C (its m.p.), and can be taken without decomposition into the gas phase using electrospray MS methods. So, at first glance to this chemist, this purported general change of gases to plasmas is not a [general, accessible, real] fourth general physical state of matter. And if I see this, in passing here, I can guarantee that there are colleagues of mine who, on hearing of this "pitch" for the implications of plasma research, have already commented similarly, in print.

Moreover, like other such topical matters at WP that appear repeatedly in articles because it is someone's favorite subject, "plasma as four state" is not verified, broadly, where the claim appears in WP articles, from the required secondary sources—including chemical. It it can be done, so it is clear that all the physical chemists everywhere ascribe to this, then include the array of best citations wherever the claim is made. If it cannot be made so unequivocally among academicians—as I am guessing must be the case—that is, if there is a static preponderance of expert opinion that is not in full agreement to this "four states" paradigm/conceptualization, then it ain't so (current representation does not cut it). If this is the case, the other expert opinions need to be stated here also, even if in the minority of those writing about it. We are not to present something as a done deal, when there are expert "hold outs".

Otherwise, note, citing of self-published academician course notes as sources—this does not help the case for persuasion at all. Reply here as you will, and I will hold breath to hear how I am fundamentally misguided. Cheers. Le Prof [a chemist who has experienced three states, for >50 yrs] Leprof 7272 (talk) 01:13, 3 July 2015 (UTC)

Thank you for writing this. It allows me to think of plasma in a different light. As well, do you have an opinion of supercritical matter? Could that be considered a fifth state? Wavyinfinity (talk) 20:01, 10 July 2015 (UTC)


When a gas is heated or subjected to strong EM radiation it ionizes. That is clear to me. Why is there no mention of plasma recombination, meaning that when it cools it will go back gaseous state and release heat, an exothermic reaction? It is like talk of water being vaporized only to produce water vapor, but condensation... nope. Rain doesn't exist.Wavyinfinity (talk) 20:07, 10 July 2015 (UTC)

Plasmas generally have both ionization and recombination processes happening simultaneously, leading to an overall degree of ionization, as described in the article. Unlike the liquid-air case, there is no first order phase transition between ionized and recombined constituents. --Mark viking (talk) 00:40, 11 July 2015 (UTC)