Talk:Tokamak

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Old stuff[edit]

"The tokamak continues to be the most promising device for generating net power from nuclear fusion" Who made that claim and what is it founded upon? There are in fact competing devices such as the polywell (http://en.wikipedia.org/wiki/Polywell)


From the quote: "The hair is analogous to the magnetic field lines needed in a fusion reactor. It turns out that it is impossible to comb hair on a sphere so that no hair sticks up".... How about if I combed the sphere into a very neat afro? every hair would stand on end, so this is not an impossibility is it?

How about if it read:

"The hair is analogous to the magnetic field lines needed in a fusion reactor. It turns out that it is impossible to comb hair on a sphere so that no hairs cross over each other (or are not parallel to each other). A strand of hair that crosses another would be equivalent to an instability in the reactor. However, a hairy doughnut can be so combed by combing along the circumference and with a slight twist, and thus adjustments to the magnetic field can be made to correct the irregularities. This allows the magnetic field to better confine the plasma"

-donville

You don't seem to understand the hairy ball theorem, I've reverted the changes you made as they're incorrect. However I will agree that the section is badly written, and a deeper physical explanation (of what the hairy ball theorem means for confining a plasma) would be good. Suggestions? -TeeEmCee 12:07, 22 September 2006 (UTC)
This is my favorite kind of critical exercise. "You don't seem understand this. I'm not going to bother explaining it in anyway, but trust me, you're wrong." What a waste of time. Eaglizard (talk) 15:27, 31 March 2009 (UTC)

Some indication as to the absolute size of the pictured tokamak would be useful.

Saying it is the "smallest" doesn't mean much without that reference.

The article states that the only way to confine a plasma is with magnetic fields. Surely a plasma can also (albeit momentarily) be confined by its own inertia. Such is the principle of inertial confinement devices (ICD) after all. --- Yes but this isnt an ICD, its a magnetic confinement device.

To say that some thing or some method is the "only way" to do something is always a dangerous and dubious statement - given no mathematical proof of that fact. Even if something is the 99% most likely way, that doesn't make it the "only way". People do need to learn to express themselves with some precision.74.163.36.177 (talk) 14:57, 8 September 2008 (UTC)

Most plasma in the universe is confined by gravity.


The explanation given in the article for the spelling of tokamak (with a final 'k', to avoid orthographic similarity with 'magic') seems quite dubious. More likely is that the 'g' of 'magnitnaya' is subjected to the typical Russian language devoicing of consonants at the end of a word.

Alodyne 04:25, 4 Feb 2005 (UTC)


to avoid analogy with the word magic

The Russian word for magic??? I'm confused. - Omegatron 00:03, May 4, 2005 (UTC)

"Tokamak" comes from Russian "toroidalnaya kamera s magnitnoi katushkoi" (toroidal camera with magnetic coil).

I thought "kamera" was "chamber"? YggdrasilsRoot 28 June 2005 12:53 (UTC)
yes (gritzko)
A key element missing in this explanation is the word "acronym".74.163.36.177 (talk) 15:00, 8 September 2008 (UTC)

http://nature.web.ru/db/msg.html?mid=1173581&uri=page4.html

Note: most probably, the author of the general idea of tokamak is Sgt. Oleg Aleksandrovich Lavrent'ev (no kidding, his work was sent to I.V.Stalin circa 1949, A.D.Sakharov reviewed that letter). "Nauka i zhizn'" ("Science and life", one of oldest Russian popular science journals) claims that A.D.Sakharov recognized scientific priority of Lavrent'ev, although I don't have the exact quote (by ADS). Dr. Lavrent'ev was working at Kharkov Physics&Technics Institute as of 2001. (gritzko)

http://ufn.ioc.ac.ru/archive/russian/abstracts/abst2145.html "Role of O.A.Lavrent'ev in raising the problem and initiating the research on (manageable?) thermonuclear synthesis in USSR" by B.D.Bondarenko, from USPEKHI FIZICHESKIKH NAUK ("Successes of physics"), a purely academic journal. Resume: although the initial idea by O.A.Lavrent'ev clearly could not be implemented in practice, the proposed original approach (i.e. plasma containment by a field) was further developed by Tamm and Sakharov into a workable solution. Scientific priority of O.A.Lavrent'ev "worth mentioning".

Name[edit]

Can anyone from russia confirm which of the two terms is official, or at least which is prevalent ?

  • 1) тороидальная камера в магнитных катушках (... in magnetic coils) - currently in article
  • 2) тороидальная камера с магнитными катушками (... with magnetic coils) - in Russian Wikipedia article

- JohnyDog 01:51, 5 May 2006 (UTC)

Looks like (2) is prevalent. Gritzko
There is actually third one, according to Merriam-Webster and other similar sources: toroidal'naya kamera s aksial'nym magnitnym polem (toroidal chamber with an axial magnetic field).
To me it seems likely that the acronym has changed over time, as the technology and design has evolved, but I've been unable to verify this. —Preceding unsigned comment added by 129.16.193.62 (talk) 11:24, 6 February 2009 (UTC)

Power generation[edit]

What is the plan for extracting the energy generated from fusion in these devices? Will it be used to heat water, or what? A5 16:08, 5 July 2006 (UTC)

Yes, the basic idea is to heat water. See Fusion_power#Subsystems for a bit more detail. - mako 19:47, 5 July 2006 (UTC)
No, there is the strong possibility of using magnetohydrodynamics to generate electricity. —Preceding unsigned comment added by 74.163.36.177 (talk) 15:06, 8 September 2008 (UTC)

Someone ought to put this up since it's in the news... http://upi.com/NewsTrack/view.php?StoryID=20060724-065917-5783r --D3matt

This really should have a section about potential uses and hazards, etc... If I had the info I'd do it. Otherwise, this thing is pretty lame.

Torus In operation[edit]

I believe there's also a Torus in operation at the University of Wisconsin-Madison.

Here's some links about it http://sprott.physics.wisc.edu/fusion.htm http://plasma.physics.wisc.edu/mst/html/mst.htm

They do have the Madison Symmetric Torus, but it's a reversed field pinch device not a tokamak. --Gabbec 07:11, 20 October 2006 (UTC)
Well, they also have the Pegasus spherical torus; does this count as a tokamak? NSTX should also be added in that case. --Gabbec 07:19, 20 October 2006 (UTC)
Pegasus's page makes a distinction between tokamaks and spherical torii, so we should probably keep them separate. - mako 02:07, 21 October 2006 (UTC)
If we're going to distinguish between "spherical torus" and "tokamak", we'd better do it in the introduction. There isn't even a Spherical torus page. I think a spherical torus is just a special case of a tokamak, especially at the introductory level. So lets just note that a sperical torus is a kind of tokamak, and include them in this article. --Dashpool 13:03, 17 January 2007 (UTC)
American writers tend to scrupulously differentiate between "tokamak" and "spherical torus" because (I am told) they are considered as separate concepts for funding purposes, although the actual difference is mainly one of emphasis. Here in the UK, "spherical tokamak" is the usage; cf. MAST, the Mega Amp Spherical Tokamak. Dashpool's recommendation is the sensible one. By the by, the plural of "torus" is "tori" - a Japanese torii is something quite different! Dave Taylor 10:26, 10 May 2007 (UTC)
The term "spherical torus" is self-contradictory - sounds typically British. Topologically, a sphere does not have any "holes" through it - but a torus does have one. A torus can be viewed as a sphere with a hole punched through it. Topologically, there exists no method to "smoothly" transform a sphere into a torus, and vice-versa, and so, a sphere and a torus are topologically-distinct in a very important way.

Shape[edit]

Should there be a reference to the Hairy ball theorem? --Bkkbrad 16:42, 10 April 2007 (UTC)

Probably. There was a paragraph on it up till this edit last December. Nobody objected to removing it at the time, probably because the theorem and its significance were poorly and maybe incorrectly explained. If you want to return it, be my guest, but please make an effort to make it understandable to the lay reader. --Art Carlson 17:11, 10 April 2007 (UTC)

Photos of the toruses being used in fusion research bring to mind the path of the center of a star orbited by a planet.

The Earth, orbiting the Sun, moves the sun just as do the planets being discovered with spectrographically detected Doppler shift in the stellar spectra. From the Earth, it looks like the center of the Universe moves, relative to the Sun. But the "center of the universe" is equated since antiquity what was always thought to be a firmament, the unmovable. Whether or not this has any secular equivalent is debatable but since antiquity, ideas of the unmoving, immovable something exist in Hindu mythology (Brahman) and other concepts. They use images like trees, for instance, to represent the unmovable.

By trying to create the Universe, are we creating that path? A hot plasma center moving in a circle? Makes a good constructionist goal image...

It would be good to have competent discussion determine this more carefully than I have here. Fusion success might be more quickly attained, though it is certainly already very substantial.

Accounting motion of the Sun caused by Earth[edit]

Photos of the Toruses being used in fusion research bring to mind the path of the center of a star orbited by a planet. The sun moves around the barycenter of the solar system, which is the actual center of mass of the solar system, and often this is outside the Sun's surface. Even Earth, orbiting the Sun, moves the sun just as do all other planets, with Jupiter being the main cause of the shift of the barycenter. Motion like this is used in the discovery of extrasolar planets found with Doppler shift in the spectra of many other stars. The center of gravity of the Sun alone moves in a torus around the barycenter.

Is that motion of the sun caused the planets taken into formal account in present day fusion theory and chamber design?

The Earth is the specific object, because it is and contains ourselves and our research and thinking, influencing us subjectively. Earth is the place from which we view the Sun year after year. Other planets and moons go out of phase quickly. But the Sun's motion in a torus is also to be scrutinized.

From the subjective view Earth, which moves -- The center of the Universe, or the center of the Sun?

The 'center of the universe' is equated since antiquity with what was always thought to be a firmament, the unmovable.

Whether or not this has any secular equivalent is debatable but since antiquity, ideas of the unmoving immovable something exist in Hindu mythology (Brahman) and other mythologies which use images like Trees, for instance, to represent the unmovable. It was called by some the Eternally Moving Unmoved Mover, and other grand, inflated phrases.

Of course, relative velocities of the Earth, Moon, and Sun are already well known with high accuracy and the motion of the Milky Way is estimated fairly closely. In other words, are established ancient concepts confusing modern thought?

By trying to create the universe, is any confusion caused by not accounting the motion of the Sun?

A hot fiery gaseous center moving in a circle makes a good constructionist goal image...

It would be good to have competent discussion carefully determine any possible remaining confusion, or a merciful professional describe the solution that was used. Fusion success might be more quickly attained, though it is certainly already very substantial. SyntheticET 03:08, 19 May 2007 (UTC)

Unimportant[edit]

But in 'Ohmic Heating' should the 20-30 million degrees Celsius but changed to Kelvin or converted to eV? Celsius is a bit obsolete in the scientific community right? —Preceding unsigned comment added by 86.8.138.110 (talk) 17:28, 2 November 2007 (UTC)

We are talking about a difference of 273 degrees on a scale where the temperature is 25 million plus or minus 5.0 million degrees. The 273 degrees fades into vanishingly-small insignificance and can be ignored. Engineers, chemists, and biologists use Celsius temperatures all the time - but we know when to make the conversion between Celsius and Kelvin whenever it is important - smart! In so many applications, what is important is the difference between two temperatures, and not what the absolute temperature is. For example, in calculating the energy that is released by a certain chemical reaction. 74.163.36.177 (talk) 15:35, 8 September 2008 (UTC)

WikiProject class rating[edit]

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 10:04, 10 November 2007 (UTC)

Successes and Failures[edit]

I think that a section should be added to this article that explains what the current abilities of a tokamak are. For instance, how long have people been able to contain plasma at fusion-inducing temperatures before it cools? I don't know nearly enough to add that myself. Rhinocerous Ranger (talk) 19:40, 27 March 2008 (UTC)

The answer to that is "not nearly long enough" - and at the bottom line, the "successes" of a tokamak are 0% and the "failures" are 100%. The same applies to all other forms of controlled thermonuclear reaction methods that hav been tried so far. The only manmade, net-energy-producing thermonuclear reaction so far is the hydrogen bomb. 74.163.36.177 (talk) 15:41, 8 September 2008 (UTC)
I don't think its fair to say that tokamaks are failures. To date, AFAIK, there has never been the expectation that they'd be net-energy-producing. They've all been intended to learn more about what was needed to build a working fusion reactor. AFAIK, they've all achieved fusion, just not net-energy production. The same can be said for the Polywell, the Farsnworth-Hirsch, and the Elmore-Tuck-Watson Fusors. EmteeOh (talk) 13:05, 3 August 2011 (EDT) — Preceding unsigned comment added by 208.65.73.39 (talk)

Questions for the article:[edit]

Here are some questions that perhaps the article could answer:

  • When attempting to read magnetic fusion publications above the ones intended for the general public, one is immediately confronted with numerous mysterious Greek symbols, letters with superscripts, and weird units of measure. I understand what Q is, and why it's important, what magnetic field strength/flux? (in terms of tesla) is, and maybe what the Greek symbol beta stands for in the context of MFE (plasma pressure?), but all of the other general parameters--and there are like 20 or so, I think--could use some explaining in language that's understandable...this would allow people without a background in plasma physics to gain a better understanding of the differing approaches that different MFE experiments have taken, and how research has quantitatively advanced from experiment to experiment. For example, differing experiments seem to be intent on maximizing one statistic or another -- gain, confinement time, temperature, pressure, or the other parameters that I don't understand...what are "good" values for each (high, low, in the middle), how have these values progressed over time since the start of experimentation, how do they effect the design and plasma, what are the parameters that ITER & DEMO are projected to have, and how can one use these parameters and measurements to assess the success of an experiment, and the progress of the science?
The answer to your first comment is that there isn't any other way. You'll just have to learn the scientific language. Also, the idea behind maximizing one "statistic" or another is simply to find out what can be done and what cannot be done. 74.163.36.177 (talk) 16:04, 8 September 2008 (UTC)
  • Would a tokamak for power production be "on" all the time, or would it generate power in a series of pulses? Why do so many current tokamaks seem to be more focused on "pulsed" experiments than "steady state" experiments?
The whole idea is that a thermonuclear reactor that produces power in pulses is very likely to be "easier" to do than on that is "on all the time". Otherwise, nobody would bother with the pulsed methods.74.163.36.177 (talk) 16:04, 8 September 2008 (UTC)
  • What are the major questions and uncertainties involved in magnetic fusion research that are yet to be answered, that could determine success or failure of magnetic fusion energy? What are the problems remaining to be solved? (I believe a lot have to do with plasma stability and "edge localized modes", along with neutron activation and degradation of operational components, but what are the relative certainties of solving each problem? Or have they been solved (enough)?)
The bottom line is that ALL attempts at making power-porducing thermonuclear reactors are failures so far, and that nobody knows where the crucial breakthroughs might occur. All we can do is to keep on trying. That is the heart of scientific and engineering research into an unknown area.74.163.36.177 (talk) 16:04, 8 September 2008 (UTC)
  • Why are most of the MFE concepts (to date) toroidal instead of spherical? On a logical level, I would suppose that a sphere of plasma (or anything) is a lot more compressable than a doughnut, and a lot easier to heat, shoot fuel into, and contain...why isn't this the case?
The whole idea of using a toroid or donut is that you can wind electromagnetic coils around one and attempt to generate a magnetic field of the right shape inside of a toroid. This is impossible for a sphere because there topologically isn't any place to wind the coils. Another imaginable possibility would be to wind the coil around an infinitely-long cylinder (a "solenoid" in the language of physicists), but of course, that is impossible. Nice to think about, though.74.163.36.177 (talk) 16:04, 8 September 2008 (UTC)
  • Are there any possibilities to achieve Q > 1 prior to ITER (ex. upgrading JET or JT-60)?
Yes, using a "stellerator", or else a laser machine like the "Shiva", but those haven't worked, either.
  • How likely is ITER to succeed, at least from a technical standpoint? Will it achieve a long term burning plasma? Are there any potentially show-stopping technical obstacles?
How likely is ITER to succeed - nobody knows, nobody knows, nobody knows! Otherwise, there wouldn't be much point in building it and trying it out74.163.36.177 (talk) 16:04, 8 September 2008 (UTC)

Maybe these would be good for the article to answer? Katana0182 (talk) 22:02, 8 June 2008 (UTC)

Current Tokamak news section needed[edit]

I had to watch the Science channel to learn that the Tokamak only operates for 30 seconds because the magnets field is not strong enough. They explained the european version will have supermagnets which will keep the plasma away from the walls of the tokamak longer.

Where is this mentioned in this article? —Preceding unsigned comment added by Ericg33 (talkcontribs) 06:50, 6 January 2009 (UTC)

Has anyone considered intermittent Laser Ignition of Deuterium-Tritium witin the Torus in order to maintain continuous operation of the plasma field? The DT and the lasers can be ignited as needed to maintain a continuous and stable plasma field. I have this concept as a combination of the US inertial laser system and the Torus approach. Calculations need to be done, but it seems the strong magnetic field of the Torus could also be used for focusing the Laser beams on the DT when needed...ie, when the plasma begins to show signs of fading towards extinguishment. Obviously this must be done with adjusting mirrors and Laser amplification when needed. The magnetic field already required to maintain the Torus seems capable of matching the energy input used at Lawrence-Livermore for DT ignition, superficially at least, but surely someone can run the numbers. Shaping the Laser charge and the US use of reflective Holraums for inertial ignition are issues that must be addressed and modified to suit the Torus.But I see no reason these problems cannot be overcome as the energy output at Lawrence Livermore now exceeds the energy input, thus there should be sufficient energy to mirror-focus and shape the Laser shots "on the run" directly onto the cryogenic DT capsules as they are dropped into the Torus as needed. Essentially what I am asking is.....Can both the Laser Photons and the DT caps be aligned for instant ignition within the Torus as needed to "maintain the flame". Can the energy being used to maintain the Torus be partially redirected to the Laser system as the plasma field fades, then be used to get off a DT shot, and then be redirected back to the Torus maintenance system within nanoseconds? Am I crazy for suggesting this? Feedback from qualified PhD's are appreciated. PS: ITER is using a Berylium compound as its inner surface wall, not ceramics.LaserPhoton (talk) 07:05, 30 December 2011 (UTC)LaserPhoton

Tokamak[edit]

Tokamak —Preceding unsigned comment added by 119.42.155.8 (talk) 17:58, 7 November 2009 (UTC)

Alternating current?[edit]

The article says that 1987 saw the first demonstration of alternating current in a tokamak. Is it correct that the tokamaks since then all use an AC plasma current? I assume that this AC plasma current is induced by an alternating magnetic field, using the principle of a transformer. How did the tokamaks prior to 1987 generate a DC plasma current? AxelBoldt (talk) 22:09, 27 February 2010 (UTC)

History[edit]

Experimental research of tokamak systems started in 1956 in Kurchatov Institute, Moscow by a group of Soviet scientists led by Lev Artsimovich.

I have a source that states that the first tokamak was created in 1954: http://www.toodlepip.com/tokamak/discovered-here.htm

--Frozen Serge 23:13, 11 November 2010 (UTC) —Preceding unsigned comment added by Frozen Serge (talkcontribs)

Nit picking?[edit]

Under "Tokomak Cooling" I cite: "A cryogenic system is used to prevent heat loss from the superconducting magnets." Should this have read instead: "A cryogenic system is used to prevent heat absorption by the superconducting magnets." Or more simply to cool the etc. More knowledgable please answer. Idealist707 (talk) 18:52, 3 January 2012 (UTC)

Major disruption[edit]

The phenomenon of major disruptions in Tokamaks is definitely real, but the paragraph discussing not only feels out of place, but is distinctly not NPV. Hpa (talk) 08:39, 18 March 2012 (UTC)

confusing[edit]

Improper wording leads to ambiguity which leads to misunderstanding of the text. — Preceding unsigned comment added by Jangirke (talkcontribs) 02:56, 30 January 2014 (UTC)

Add section about theories how engergy is supposed to be harvested from the fusion chain reaction[edit]

See above. :)