Archives

Escalating response to vandalismEdit

For my own reference (but I recommend that you use them too): Wikipedia:VANDAL#Warnings

  • unintentional vandalism/test: "didn't appear constructive"
{{subst:uw-vandalism1|PageName}} ~~~~
  • suitable for intentional nonsense or disruption: "unconstructive edits ... appear to constitute vandalism"
{{subst:uw-vandalism2|PageName}} ~~~~
  • "please stop" for use after level 2 warning: "you may be blocked from editing"
{{subst:uw-vandalism3|PageName}} ~~~~
  • last warning for vandalism: "you may be blocked from editing without further notice"
{{subst:uw-vandalism4|PageName}} ~~~~

For repeated vandalism by an IP user it is helpful to take the following additional steps:

  1. Trace the IP address (e.g. http://www.domaintools.com/) and add {{whois|Name of owner}} to the user talk page of the address. If it appears to be a shared IP address, add {{SharedIP|Name of owner}} or {{Shared IP edu|Name of owner}}. The OrgName on the IP trace result should be used as the Name of owner parameter in the above three templates.
  2. Particularly if the IP address is registered to a school or other kind of responsive ISP, consider listing it on Wikipedia:Abuse response.

DNSSTUFF is THE spot to trace IP's.

Do you have some time to review NIF?Edit

I think the National Ignition Facility article has been stable for some time now, and I'm considering moving it to the GA/FA process. Do you have time to give it a good read-over? Maury Markowitz (talk) 14:39, 25 February 2011 (UTC)

Sorry it took me a while to get to this. As you probably saw, I made a few changes, but nothing major. As far as I can tell the article is accurate and on the whole it is well written. It is sometimes a little confusing, but that is hard to avoid with the complex subject matter. What would perhaps be helpful is a summary of the most important numbers, maybe in table form — electrical energy input, laser energy to the target, expected fusion output, predicted energy required for economical fusion energy, temperature achieved, temperature predicted, temperature needed for economical operation, maybe also initial cost estimate and final cost. The rep rate should be mentioned (and the requirement for commercial fusion), or did I just overlook that? And, of course, the status should be updated.
Cheers, Art Carlson (talk) 08:34, 5 May 2011 (UTC)

Need help on naming this List of plasma (physics) applications articlesEdit

The List of plasma (physics) applications articles has almost all elements sources artificial creation and driven mechanisms by plasma physics. I just don't know what to name it to fit its standards. Your probably gonna think It has to many plasma related sources but its a good and helpful thing to put.Especially if You wanna find a certain passion plasma field. Shawn Worthington Laser Plasma (talk) 17:54, 23 November 2011 (UTC)

Isn't that what Category:Plasma physics is for? --Art Carlson (talk) 08:33, 24 November 2011 (UTC)

Category:Plasma physics would be harder to find for new comers on wikipedia. It doesn't show up on the search bar, plus sometimes they don't allow it to get to big so they add it to sub categories. It doesn't have all the plasma sources and technology as List of plasma (physics) applications articles just only it has the notable ones.Index of wave articles is kinda the same thing with a category. Hopefully it doesn't get deleted what do You think will happen to it.Shawn Worthington Laser Plasma (talk) 17:49, 24 November 2011 (UTC)

I think you're reinventing categories with all the problems and no advantages. --Art Carlson (talk) 07:31, 25 November 2011 (UTC)

People would be thrilled and educated to see all plasma physics topics. Nothing to lose and a lot to gain knowledge on plasma. It will not interfere with any other articles it will only make more plasma physics articles more popular and easier to locate.Shawn Worthington Laser Plasma (talk) 20:01, 26 November 2011 (UTC)

Keep fighting the good fight.Edit

Hi Art,

Good to see you still active here.

I just saw that some of the fringe-proponents are back inserting dubious sources into the plasma cosmology article. I tried to clean things up but don't know for how long I'll be allowed to by the administration at this website which has become more and more simpatico with the WP:RANDY ideals of Wikipedia.

A few things:

  1. I think that IEEE Transactions really should be removed. Tim Eastman basically was handing over journal rights to Tony Perrat as a favor and there is almost no oversight of the papers that are published there. Recently, Astrophysics and Space Science stopped publishing fringe theories as a move by the editorial board to control some of the more outlandish things that had come out of that work, but generally the Ap&SS articles are of slightly better quality than IEEE Transaction rants. I left a few of those sources in, and maybe for illustrative purposes they're okay, but most of them are utterly unvetted as far as I can tell. The last IEEE Plasma Transactions special series on cosmology was especially embarrassing with Tony Perrat going on and on about petroglyphs, of all things (there seems to be more synergy between the Alfven students and the catastrophists in the last five years).
  2. There was a lot of material I removed which was about Birkeland currents which seemed mildly inoffensive but distracting from the main point of the article being about cosmology.
  3. I think some of the additions by the proponents are good. There is a slightly better explanation of Alfven-Klein models. The wall of text about Perrat's 1982-6 simulations seemed a bit over-the-top, but there seems to be not too much reason to exclude it as it has actually not really moved anywhere since then and illustrated well how the proposal is essentially moribund. However, it's a bit strange that plasma cosmology's hallmark simulation is about galaxy formation which is only one tiny part of mainstream cosmology. In plasma cosmology, there is little in the way of distinguishing between astrophysics and cosmology though the subjects themselves are more and more distinct as the years have gone on. This may have more to do with their general dislike for cosmology as a topic than it says anything about a particular research approach. The plasma cosmology "scaling" arguments of the plasma cosmology proponents are all pitched at that angle, anyway.

Let me know if there is any more help you need.

209.2.217.151 (talk) 18:39, 12 May 2012 (UTC)

I'm afraid I—or rather the article—needs a lot of help. I don't have as much time to invest as I did the first time around, but I am uncomfortable with the way the article is changing. The difficulties are inherent in any article on fringe science. I think we all agree that there should be an article on this topic, but it can't be written with proper secondary sources, since there aren't any. I think we should be careful, though, about removing sources, such as IEEE, first because they will keep coming back to haunt us anyway, second because they are the only basis of PC, and third because PC disciples have a right and a need to see these presented and commented on in an intelligent way. Art Carlson (talk) 09:41, 17 May 2012 (UTC)

Possible ball lightning videoEdit

Hi, Art. I saw that you had commented on the article on ball lightning and that you're a plasma physicist. I just came across a video, allegedly from a security camera in Cilandak Town Square in Jakarta, Indonesia, 9/11/2011. It's being presented as an "angel", so lots of really low grade debunking is going on, I mean, UPI wire service is even stooping to cite YouTube commenters as their source for calling it a hoax. Thing is, it looks nothing like an angel, and I think any hoaxer who intends to put out an "angel" video and is good enough to get lighting details right would be good enough to make the thing have some resemblance to an angel. It looks like a plasmoid to me. Here's the original video: "Unknown Winged Creature Caught on Camera" Here's one with magnification, slow-motion and extra contrast: "'Winged Being' Chased by Security Guards (Indonesia)!" (mute it and skip to 0:18. Pay no attention to the crazy lady. The inverted video at about 5:00 also shows some extra detail.)

To save time, I'll just quote from a post I just wrote on it, mostly before I considered the possibility that it was ball lightning. [commenting on a blog called: "The Big Study"]

On the video itself, it seemed like a bad fake to me at first. After watching it several times it now seems like either a good fake or perhaps genuinely anomalous. Since apparent object (AO) looks a lot like a caustic, at first I suspected either a flashlight beam shining on the spot where the AO appears, or perhaps someone off camera shining a light obliquely on the camera and creating a lens flare. Neither of these explanations work. A flashlight beam would be distorted by the surfaces upon which it shines, such as the pavement and the side of the planter box. The observed motion also seems uncharacteristic of a flashlight. A lens flare would not cause the indirect lighting seen on the corner of the left planter or on the storefront above the AO. These spots brighten simultaneously when the AO seems to emit a flash, just before it reaches its lowest point.
... in general it appears to me to be like a surface of revolution. At first it is toroidal and similar in cross section to a magnetic field. ... After it bounces, it again looks like a magnetic-field shaped plasmoid, but with the axis now inclined to the right. Being partially transparent, yet itself emitting light, where parts overlap from the point of view of the camera, the AO appears brighter and more opaque. There may be hints of a radial filamentary structure. The light intensity seems to vary rapidly from certain directions, for instance there is a flickering visible on the corner of the left planter.
The motion at first seems like a physical, elastic object being decelerated and strained by hitting the ground, then bouncing back upwards. But since the initial motion was straight down and it hit a level surface, yet rather than bouncing straight upward, it instead moved with a accelerating, curved rightward component, it seems perhaps to be self-propelled, but it may instead be moving in response to a local EM field, perhaps concentrated by the rebar in the concrete pavement.
After the AO goes off screen, the patch of ground that it hit is slightly lighter than before - it appears drier than the surrounding pavement, or perhaps the floor polish is gone, or perhaps it's even glowing a bit. The effect fades over a few seconds but does not go away entirely. It seems likely that there was local heating in that spot. This area seems to attract attention from the men afterward, implying that there was something unusual to see there.
My guess is that if it isn't a hoax, it's the first video of real, natural ball lightning. The expected shape, size, behavior, appearance and effects all match. It also might explain why the men didn't continue after it - it may have gone through a wall or simply fizzled out.

Looking at the video some more, it wouldn't have been that easy to fake. The lighting is right, or at least plausible. Details of dark areas are revealed by the light that could not have been revealed by simply lightening the original video. It could still be done with more advanced methods, multiple takes, and compositing - if the intent were to create a ball lightning hoax or a movie special effect. But to do an angel hoax video? It seems unlikely.

Other notes: it seems to be outdoors and raining in the video. [edit: outdoors, not raining] I wasn't sure if it was just compression artifacts at first. The slowed, contrast-pushed video does show what appear to be filamentary and sheath structures, as well as a mushroom-shape in the initial frames as a column of glow discharge is created between the plasmoid and the ground. The inverted video reveals turbulent-looking structures in the periphery of the plasmoid.

What do you think? Could it be a real video of ball lightning?Enon (talk) 06:03, 21 May 2012 (UTC)

I have found a potentially corroborating video taken by the bystanders who appear in the security camera footage. I'll hold off on analysis unless you're interested. "Gokil any strange objects in Citos jatoh" Enon (talk) 21:43, 21 May 2012 (UTC)

I hardly know how to begin to answer your question. Ball lightning is a term for a collection of reports that may or may not be the result of a single phenomenon. Until we have a theory that can account for a large fraction of the reports, the question of whether a particular video is "really" ball lightning is meaningless. On the other hand, if you are interested in this mystery, there is no other place to start than looking at many reports, and a video has many advantages over eye witness reports.
Ball lightning is not near the top of my interests at the moment. If I wanted to study this video scientifically, I would start by interviewing the witnesses, examining the optics, and reading weather reports. If there really is a second video, then you can do a lot more. You have a separate optical and electronic chain, a different perspective, and you can combine the videos to get 3d info. The bilateral symmetry of the image strongly suggests rotational symmetry (unless it's really an angel). Dark features in the middle suggest a toroidal shape. Of course, the plasmoid hypothesis of ball lightning has a lot of problems, so I wouldn't get hung up on that explanation. The behavior of the people seems to rule out any optical effect related solely to the camera or the perspective, and the history of the video as being an angel makes me discount (but not eliminate) a hoax, but maybe only because it would never have occurred to me to call that apparition an angel.
All in all, it sounds like you are approaching the report about like I would, if I decided to approach it at all. I hope you have fun, and maybe you or someone else can really learn something from this.
Art Carlson (talk) 07:50, 22 May 2012 (UTC)
Thanks for answering. Unfortunately the 2nd video (cellphone) only gets light reflected from the object, so not much 3D information, though it does give color and sound missing from the original (blue-white light, roaring sound followed by explosion). The reflected flickering may be correlated with the original video. It also shows the destruction of a big piece of the pavement where the thing hit, gives indications of the time of day (likely before dawn) and details of the surroundings that may help locate the incident. The weather seems to have been clear immediately above the area. (May be misleading, though - Atlanta had a tornado hit when it was clear immediately above, with a storm front a few miles away.) There also is a glimpse of what may be the corner of a thick steel plate under the destroyed pavement. I'm trying to get more information of the sorts you suggested, but the language barrier is slowing me down. I have found a few potential independent witness reports of this incident and non-specific mentions of newspaper stories but the people who made them are hard to track down.
But what I really wanted to know is your opinion as a plasma physicist of how serious are the problems of the plasmoid hypothesis are. So far as the videos show, the object only lasted 2 or 3 seconds, so it seems to me that this would relax the requirements on the plasma. If the conductivity and magnetic field were high enough, perhaps a 2m diameter plasmoid could store enough energy to last that long? (Given the effects, I think it would have to store at least 0.5MJ, maybe much more.) My seat of the pants guess (based on seeing videos of HV transformers exploding, the plasma lasts 0.1s-1s after the circuit is interrupted) is that the conductivity would need to be at least 3-30 times what is typical for an air plasma to sustain the magnetic field for 3 seconds. Is that a plausible estimate, or ...? Is there some other constraint such as maintaining heat or ionization that would kill such a plasmoid in less than 3 seconds, even if the conductivity were initially high enough? If such a thing did somehow come into existence, because of its magnetic field, it should be attracted to a big plate of steel, right? Once it has spent most of its energy breaking up the pavement and heating and magnetizing the steel, somehow it flips to being repelled by it (Curie point + Lentz's law maybe?), but without the steel, the inductance would fall suddenly, perhaps giving a flyback transformer effect that causes the plasma to dump its energy suddenly and explode. That's my working hypothesis, anyway.Enon (talk) 19:07, 23 May 2012 (UTC)
I hadn't looked at the article for a while. I thought there were more technical details of the problems with the theories in there.
Probably the biggest problem I see with the plasmoid hypothesis is the virial theorem. The pressure of the plasma cannot be contained by the magnetic fields. On the contrary, the fields contribute to the tendency to expand. A free-floating plasmoid pretty much has to be confined by atmospheric pressure, so the energy density cannot be much over 1 bar = 100,000 Pa = 100,000 J/m^3. 10^5 J is the kinetic energy of an automobile at highway speeds, see Orders of magnitude (energy)). It would take 100 seconds to lose this much energy by radiation or conduction at a rate of 1 kW. This energy density is close to your 0.5 MJ in a 2 meter ball. You'd have to go into details, but these numbers do not completely rule out a plasmoid in this case.
The next thing I worry about is buoyancy. The density of a respectable plasmoid is a good vacuum in comparison to air, so it should float away like a helium balloon, if not faster. On the other hand, depending on exactly how it is constructed, it may interact magnetically with the environment, and I could easily imagine those forces to be big enough to overcome the buoyancy. Again, a problem, but not a knockout.
The remaining difficulties are harder to get a grasp on. Things like conductivity, radiation, recombination rate. It can't be easy to maintain a highly ionized plasma in close proximity to air. With a hydrogen plasma, as used in fusion power research, the atoms are stripped of electrons at a relatively low temperature so you mostly have to deal with bremsstrahlung radiation, but an oxygen/nitrogen plasma will always have some electrons attached to the nucleus. This allows collisional excitation of the bound states followed by radiation as the excited electron drops back down to its groud state. This form of radiation is much more intense and makes it hard to maintain a plasmoid for even a fraction of a second.
I don't know if that answers your question. It's not a shoe in, but may not be any more far-fetched than the alternative proposals.
~~
Thanks, that gives me a better handle on the physical limits. Enon (talk) 00:02, 25 May 2012 (UTC)

Plasma CosmologyEdit

Hello Art, by removing references to Plasma Cosmological explanations for COBE & WMAP dating from 1988, 1995, and as recently as 2007, you allowed the continuation of the claim that Plasma Cosmology advocates had made no attempt to explain COBE or WMAP data. This is in direct contradiction to material referenced on the site as published on Eric Lerner's Big Bang Never Happened website. Lerner has documents immediately prior to and after COBE that explain the data. Further evidence that can be used by Plasma Cosmologist to refute claims is provided on other Wikipedia articles such as the one for "CMB Cold Spot"

In any case, the data is also challenged by world renowned Radiologist Ari Brynjolfsson who has published his work at http://plasmaredshift.org. As Head of the U.S. Army and United Nations Radiological Divisions, Ari Brynjolfsson is the world's foremost authority on the topic of the behavior of electromagnetic radiation and light in plasma. His conclusions on the matter weigh far more as an authority than any potential Wikipedia undergrad student editor.

In that, the works of Dr. Eric Lerner, Dr. Anthony Peratt, Dr. Ari Brynjolfsson, and Dr. Robitaille can cite evidence that contradicts the claim that "no explanation by Plasma Cosmologists" has been provided. Then an alternative should be proposed.

Need I remind you, that this Wiki has received dismal ratings on trustworthiness, etc. Obviously, your wikipedia entry on this topic is in need of desperate revision and should be handed back over to a more reputable authority in the field. I believe the history of this topic shows that Eric Lerner himself was once its editor. He should be restored to it. — Preceding unsigned comment added by 71.92.165.133 (talk) 21:31, 30 May 2012 (UTC)

Please be patient for a day or two until I have time to respond to this. I still have objections to many of your edits, but right off it looks like the claim about COBE will have to be modified in light of the 1995 Lerner paper. Art Carlson (talk) 08:48, 31 May 2012 (UTC)
  • Dr. Ari Brynjolfsson, http://plasmaredshift.org: Private websites and unpublished papers are almost never considered to be reliable sources.
  • Dr. Pierre-Marie Robitaille, COBE: A Radiological Analysis and WMAP: A Radiological Analysis: Neither of these papers even mentions plasma, so there is no relevance to plasma cosmology. In addition, Progress in Physics is a problematical source at best.
  • Eric Lerner, Intergalactic Radio Absorption and the COBE Data, Astrophysics and Space Science, 227: 61-81, 1995: This is indeed a "proposal based on plasma cosmology to explain the cosmic microwave background radiation (CMB) [that] has been published since the Cosmic Background Explorer (COBE) results were announced in 1992", so at least that line will have to be fixed. In that paper, Lerner argues that his model can explain both the fidelity of the CMB spectrum to that of a black body and the low level of anisotropies. WMAP did not significantly change either of these results. What it did do is provide a detailed spectrum of the anisotropies. The form of the spectrum can be explained within the LCDM model with a choice of parameters that are consistent with other observations. There is no other theory that can do this. Plasma cosmology, in particular, has never made an attempt to do so.
Art Carlson (talk) 20:46, 4 June 2012 (UTC)

VandalismEdit

Hi, I just noticed you reverted a vandalism edit on Fusion power but the talk page of the user was empty. I put a vandalism warning on it and I encourage you to do as well each time you revert vandalism so that other wikipedians know that the concerned users/IPs have already vandalised some pages. Thanks in advance. --XonqNopp Tk 14:39, 6 June 2012 (UTC)

Good idea. I'll try to cultivate the habit. Is there any easy way to do that? Art Carlson (talk) 16:33, 6 June 2012 (UTC)
I think the best thing to do is have a look at WP:VANDAL, especially the section 4.1 where you will find how to warn the users... If you have any question, don't hesitate ;-) --XonqNopp Tk 10:33, 11 June 2012 (UTC)

Galaxy section of plasma cosmologyEdit

Hi Art,

I left a note on the Talk:Plasma cosmology page, but thought I'd buzz you here too.

The galaxy formation bits of plasma cosmology are certainly the most fleshed-out proposals that group generated, but they haven't been discussed by independent sources, that I can find. Can you find any mention of these by independent groups?

I removed the section because there is a lot of special pleading and rabbit hole theorizing going on that is hard to untangle. For example, the claim that "Computer simulations in the 1980s showing the cross-section of two plasma filaments coalescing also mimicked the shape of real galaxies." is actually incorrect. Peratt's simulations do not "mimic" the shape of real galaxies any more than any other spiral structure. This would be like saying that "hurricanes mimic the shape of real galaxies". It's incorrect. The simulations mimic the shape of "spirals" but the details of galactic morphology are completely unaddressed in any of the primary sources.

There were other problems too. For example, the article seemed to be claiming that Eric Lerner invented the dense plasma focus because he was inspired by his own quasar model. This is just plain not true!

Anyway, the section was so problematic, but, as is often the case, long explanations don't get very far on the talk pages of controversial articles so I augment here. It may be possible to write a small bit about Peratt or Lerner's ideas, but the emphasis and form of the writing and ideas presented in that section just were not helping anything.

50.74.135.246 (talk) 22:17, 7 June 2012 (UTC)

I have a lot of ambivalence about this article. I sympathize with those who want Wikipedia to say something about every topic, including or especially fringe topics, but it is hard or impossible to handle fringe topics at the same level of quality as other topics. When I make an effort to do this, partly motivated by a desire to teach starry-eyed dreamers some real science, I usually end up straddling the line to original research. I believe my OR is right and good, but it is still OR. My level of patience with proponents of fringe topics has probably dropped considerably since I worked extensively on this article. Maybe it really is best to return it to its one-time state of an article almost solely on Alfven's cosmology. If you want to do that, I won't fight you. Art Carlson (talk) 18:56, 10 June 2012 (UTC)
Well, it has come to me holding my nose and writing a section about galaxies and quasars. Please read it over and decide what you think. Goodsheard1 (talk) 02:40, 13 July 2012 (UTC)

Plasma physicsEdit

I am getting realy tired of fighting people that are undoing this edit. Maybe you can somehow amend it yourself as I see it is an important topic for you.

The problem is that Plasma is one of the basic states of matter and that is much more fundamental than for example "plasma gun" with which it has the same standing.

When I first searched for Plasma I got totaly confused as it is not outlined clearly in Plasma phisics part and definitely not here where plasma phisics is just one of (last) of mirriads of meanings listed.

Plasma is one of the crucial materials of the universe and basic state of matter and it needs to be utlined in that sense clearly and before all other meannings, othervise it is confusing.

Anyway, you can keep undoing but you are not making wikipedia better. — Preceding unsigned comment added by 31.147.7.108 (talk) 11:51, 15 October 2012 (UTC)

Did you read my edit comment, where I cited the Wikipedia policy that was the basis for my reversion?
rv good faith edit according to MOS:DABENTRY: "Include exactly one navigable (blue) link ... Keep the description associated with a link to a minimum, just sufficient to allow the reader to find the correct link."
There are more pages linking to Cytoplasm than to Plasma (physics), so you shouldn't assume that everyone shares your interest in physics. But maybe if you explain more precisely what you were looking for and how you got confused we could find a way to avoid that trap without confusing others.
Art Carlson (talk) 14:47, 15 October 2012 (UTC)

Aneutronic FusionEdit

Hi Art,

Did you really read and understand Malcolm Haines' paper before deleting my paragraph on reverse non-equilibrium plasmas like found on the Z-Machine?

If you disagree, let's discuss!

The physics of the Z-machine plasma is fairly different from a classical hot plasma physics. This is a fully non-equilibrium plasma, from several aspects. - At first the ion and electron temperatures are fairly, very different. Two orders of magnitude.

When the electric potential is applied to the wires, with a rise time of 100 ns, this is equivalent to a 10 MHZ HF current, so that the current pfows at the periphery of the wires, producing a metallic plasma. But the cores of the wires stay at low temperature. When the wires implode, their cores remain solid, metallic, not transformed into plasma. It explains the good focussing on the axis.On another hand, there is no Raleigh Taylor instability.

Well, after a 100 ns fall, the metallic wires form a thin plasma chord ( see Malcom Haines paper , PRL 2006 ), whose diameter is 1.5 mm

The impact velocity is about 600 km/s. Collisions transform this radial velocity into a randomized thermal velocity. We have to take account of three different kinds of collissions: e x e collisions i x i collisions e x i collisions.

The characteristic times of the two first are very short (calculated from Coulomb cross sections). Thermalization of ions occurs in 36 ps.

The characteristic time of e x i collisions gives the time to get local thermodynamic equilibrium. This last is quite long ( see the paper of Haines ), with respect to e x e and i x i characteristic times ( mean free path, with respect to such encouters)

So that, due to thermalization process : - The electron gas get a temperature Te, with an almost Maxwell-Boltzmann velocity distribution. - The ion gas get a temperature Ti, with an almost Maxwell-Boltzmann velocity distribution.

But Ti >> Te Additional phenomena play a role in this fairly non equilibrium conditions. One was described by Haines in 2006. In effect, if one computes the ion temperature, due to thermalization, one finds only about 900 millions degrees. But a much higher ion temperature is measured (by enlargement of spectroscopic lines, due to doppler effect) or deduced from the Bennet equation, which express the fact that the ion pressure balances the magnetic pressure (90 Mb)

From those two, the temperature is "over two billions degrees" ( title of Haines' paper, 2006). In fact, this ion temperature, measured, grows to 3,7 billions degrees, when the plasma chord has already stated its expansion !

Yonas asked : where that energy comes from ? Normal Joule effect ? Impossible. The calculation (Haines, 2006) gives a characteristic time of 8 ms. Too large....

Haines says : it comes from an anomalous transfer of energy, due to MHD instabilities, forming tiny clusters made of ions. This reinforce the transfer of energy between electrons and ions. It's a turbulent Joule effect. Haines calls it "viscous pinch" ( opposed to resistive pinch )

So, the dynamics of this medium is somewhat complex. BUT: the measured electrons temperature is 3 eV; The measured ion temperature is 300 eV; Ti/Te = 100 !!!

The radiation loss, due to Bremsstrahlung corresponds to the acceleration of an electron, when passing by an ion. This loss is proportional to the velocity of the electron, which grows as the square root of Te.

In a plasma, the heavy species' velocities ( ions or clusters of ions ) are always neglectible with respect to the high electron velocity. Even when Ti>>Te.

So that the Bremsstrahlung loss depends on two parameters : - The square root of the electron temperature - The square of the target's electric charge Z. It does not depend on the ion velocity ( i.e. Ion temperature)

In a boron-hydrogen plasma at 1 billion degrees, if Te = Ti, the bremsstrahlung loss is 1,8 times the energy produced by fusion reactions.

If Te = Ti/100 this loss is 10 times smaller.

Aneutronik (talk) 15:09, 25 October 2012 (UTC)

I'm a pinch man myself. I did my doctoral work on FRCs, a sort of theta pinch. So yeah, I understand what's going on here. I realize that pinches tend to produce plasmas with T_i greater than T_e, sometimes much greater. This is a hypothetical discussion, so I am willing to assume any values of T_e and T_i. The thing is that it's the ions that have to be kept hot if you want fusion. There are many effects that may cause the ions to lose energy, especially various instabilities, but the rock bottom energy loss will be that due to classical collisions with the electrons. The colder the electrons are, the greater this loss term will be. That's why making the electrons colder does not allow you to get around the power balance problem of aneutronic fusion. (Being out of equilibrium doesn't help either, but that's a different argument.) Art Carlson (talk) 19:31, 25 October 2012 (UTC)

Hi Art,

Seems we need to talk; meanwhile I'd like to make sure you're familiar with:

"Ion Viscous Heating in a Magnetohydrodynamically Unstable Z Pinch at Over 2 � 109 Kelvin" Haines et al, 2006:

http://www.mhdprospects.com/pdf/Haines_paper.pdf

and

"Pulsed-power-driven cylindrical liner implosions of laser preheated fuel magnetized with an axial field" Slutz et al, 2009:

http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PHPAEN000017000005056303000001&idtype=cvips&doi=10.1063/1.3333505&prog=normal&bypassSSO=1

and

"High-Gain Magnetized Inertial Fusion" Slutz et al, 2011:

http://prl.aps.org/abstract/PRL/v108/i2/e025003

and

http://www.sandia.gov/pulsedpower/maglifpres/Slutz_MagLIFconcept.pdf

Aneutronik (talk) 09:51, 26 October 2012 (UTC)

How about you tell me where you want to go with this first. Are you still talking about the power balance of a fusion plasma when T_i is much greater than T_e? Did you understand the point that colder electrons sap energy from the ions faster? Art Carlson (talk) 10:50, 26 October 2012 (UTC)

Plasma UniverseEdit

I can hear you *sigh* from here! But, since you had some good ideas about what the plasma universe meant, just a heads up there is a discussion going on at Talk:Plasma cosmology#"plasma_universe" definition from secondary sources and at Talk:Anthony Peratt, see section Book "Physics of the Plasma Universe". I'm also idly toying with the idea of a disambiguation page, see Talk:Plasma Universe#Disambiguation. Aarghdvaark (talk) 13:52, 20 November 2012 (UTC)

I saw that discussion (and sighed deeply when I did). The trouble is I don't remember what the question was. Could you remind me what the proposed or disputed edit to Plasma cosmology was that we are trying to improve or resolve here? Art Carlson (talk) 14:36, 20 November 2012 (UTC)

Deuterium-deuterium fusionEdit

Hi. I tried to send you this by e-mail, but I guess you didn't see it.

I notice that you made an edit to Nuclear fusion back in 2005, including discussion of the deuterium-deuterium reaction ([1]). I have modified the article a little bit, adding in the actual reaction:

5D → helium-4 + 2 neutrons + helium-3 + proton

You made a calculation of the energy by taking the energy of the above divided by 2. But I think it should be divided by 2.5 since it uses five deuterons. Can you comment? Doesn't this affect the table in which you give the power density etc.? Eric Kvaalen (talk) 07:38, 1 April 2014 (UTC)

My email address has changed several times since I last set it. Sorry. I fixed that now. I think my calculation is correct, but give me a couple days to find time to think about it in peace. Either way, it should probably be explained better in the article. Art Carlson (talk) 08:36, 1 April 2014 (UTC)
I started a new job about the time of this exchange, so the question was off my radar. Looking at it now, the key phrase is "We count the 2
1
D
-2
1
D
fusion energy per D-D reaction (not per pair of deuterium atoms) as ...", emphasis in the original. In Nuclear_fusion#Requirements we gave the formula for the rate of D-D reactions as  . Half of the DD reactions will take the T branch (reaction 2i) and produce 4.03 MeV and then, through reaction 1, an additional 17.6 MeV. The other half of the time, the DD reactions will take the 3He branch (reaction 2ii) and produce 3.27 MeV. The average energy realeased every time there is a DD reaction is therefore (4.03+17.6+3.27)/2. Dividing by 2.5 would make no sense here. This can (perhaps) be made more obvious by writing the average this way: (4.03+17.6)*50% + 3.27*50%. I will make this small change in the article. Does that adequately clear up the confusion? Art Carlson (talk) 18:19, 24 July 2014 (UTC)


I have only now found your above reply! (You should ping me. See Template:Ping.)
If we put deuterium into some future reactor, we will get 24.9 MeV for every five deuterons. That comes to 4.98 MeV per deuteron. That is the number which tells us how much energy we get for the amount of deuterium used. The number you give in the table on the other hand relates to the power, that is, the rate at which energy is created (because the rate-limiting step is the D-D reaction and the D-T reaction easily keeps up). I think I'll make a remark to that effect in the article. Eric Kvaalen (talk) 14:04, 28 May 2017 (UTC)

Fusion Task ForceEdit

Dear Art,

You have quite the reputation. We have actually been interacting for a number of years, on the web. I have an appreciation for your shrewdness in physics as well as your level of knowledge. I have been working for several years to improve the level of information about fusion on Wikipedia. It is a big problem, and it will take many people to solve. I recently decided I would make this more formal and form a Wikipedia Fusion Task force:

http://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Physics#Proposal_-_A_Fusion_Research_Task_Force

You were the first person I wanted to reach out to, to see if you would be interested. Let me know if you are. WikiHelper2134 (talk) 19:39, 13 April 2015 (UTC)

Dear 2134,

I don't come by Wikipedia very often anymore, so I just now saw your message. I see the proposal didn't get a lot of response and has since been archived in

https://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Physics/Archive_May_2015#Proposal_-_A_Fusion_Research_Task_Force

I have been out of fusion a long time now, but I probably haven't forgotten everything yet, so I might be able to help. It's not my primary interest any more, so I wouldn't be doing much heavy lifting. How do you see this working?

One thing that caught my eye in your proposal is that you think the triple product needs clarification. Why do you think Lawson_criterion#Extension into the "triple_product" is inadequate?

In any case, good luck. Your devotion is appreciated.

Art Carlson (talk) 09:12, 9 June 2015 (UTC)

ArbCom elections are now open!Edit

Hi,
You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 22:13, 30 November 2015 (UTC)

ArbCom Elections 2016: Voting now open!Edit

 Hello, Art Carlson. Voting in the 2016 Arbitration Committee elections is open from Monday, 00:00, 21 November through Sunday, 23:59, 4 December to all unblocked users who have registered an account before Wednesday, 00:00, 28 October 2016 and have made at least 150 mainspace edits before Sunday, 00:00, 1 November 2016.

The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail.

If you wish to participate in the 2016 election, please review the candidates' statements and submit your choices on the voting page.

ArbCom Elections 2016: Voting now open!Edit

 Hello, Art Carlson. Voting in the 2016 Arbitration Committee elections is open from Monday, 00:00, 21 November through Sunday, 23:59, 4 December to all unblocked users who have registered an account before Wednesday, 00:00, 28 October 2016 and have made at least 150 mainspace edits before Sunday, 00:00, 1 November 2016.

The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail.

If you wish to participate in the 2016 election, please review the candidates' statements and submit your choices on the voting page. MediaWiki message delivery (talk) 22:08, 21 November 2016 (UTC)

ArbCom 2017 election voter messageEdit

 Hello, Art Carlson. Voting in the 2017 Arbitration Committee elections is now open until 23.59 on Sunday, 10 December. All users who registered an account before Saturday, 28 October 2017, made at least 150 mainspace edits before Wednesday, 1 November 2017 and are not currently blocked are eligible to vote. Users with alternate accounts may only vote once.

The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail.

If you wish to participate in the 2017 election, please review the candidates and submit your choices on the voting page. MediaWiki message delivery (talk) 18:42, 3 December 2017 (UTC)