Talk:Tokamak

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"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 infact 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)

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 after all. --- Yes but this isnt an ICD, its a magnetic confinement device.

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)

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".

Contents

[edit] Name

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

[edit] Power generation

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)

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.

[edit] Torus In operation

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)
US 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 torii is something quite different! Dave Taylor 10:26, 10 May 2007 (UTC)

[edit] Shape

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.

Earth, orbiting the Sun, moves the sun just as do the planets being discovered with spectrographically detected Doppler shift in the stellar spectra. From 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 umoving 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.

[edit] Accounting motion of the Sun caused by Earth

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)

[edit] Unimportant

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)

[edit] WikiProject class rating

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)

[edit] successes and failures

I think that a section should be added to this article that explains what the current abilities of a tokamak are. For instance, how lone 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)

[edit] Questions for the article:

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 in superscript, 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?
  • 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?
  • 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)?)
  • 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?
  • Are there any possibilities to achieve Q > 1 prior to ITER (ex. upgrading JET or JT-60)?
  • 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?

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