ITER (or: Fun With Nuclear Fusion)

[rhoenix]

Source website: +http://www.iter.org/

Even approaching this as a layman (I confess, I found it while researching stuff for my scifi story idea), I found this site fascinating.

(quoted from the article on the site, but without quote tags, as they hide the link color in the theme I'm using)

Physics Basis




The physics assumptions on which the design and performance of ITER are based have been defined and developed by the Joint Central Team (now International Team) primarily through its Physics Unit together with fusion physicists throughout the Parties. A detailed summary of the current knowledge and understanding of ITER physics in particular and of tokamak physics in general was pub lished in 1999, and its application to the current ITER design is summarised in the ITER Final Design Report Technical Basis. ITER physics is based on data collected on the present experimental tokamaks, physics models for different plasma processes, and numerical codes created for extrapolation of the plasma performance to the ITER scale and parameter range.

To keep this information up to date, the whole fusion physics community both inside and outside the ITER Participants pools its knowhow and coordinates its development through the International Tokamak Physics Activity (ITPA). Topical Groups provide inputs in each of the main physics areas and report annually to the ITPA Coordinating Committee. This "Physics Committee" sets the R&D Research Priorities for Fusion Physics.

Based on this joint work, the following assumptions have been made to derive the plasma parameters:

1. the plasma will operate in the "ELMy H-mode", i.e, with edge-localised low amplitude mhd modes and in the "high confinement" regimes observed in present experiments: the extrapolation to be used for the parameters of an ITER-size plasma will be determined by the Confinement Topical Group; the ratio of plasma to magnetic pressure, normalised to the factor I/aB, bN, shall be < 2.5, where I is plasma current, a minor radius, and B toroidal field on axis; the density shall be below the Greenwald density (defined as I/pa2); the degree of helical twist of the field lines, measured by the "safety factor", q, on the toroidal flux surface 5% from the plasma edge, shall be ~3; the impurity level in the plasma shall be such as to retain its effective atomic number below 2;
2. the plasma will be operated in a well-controlled divertor configuration.

The basic physics elements of the ITER plasma performance have been successfully tested in present day experiments. However, an integrated simulation of a fully ITER-like plasma is not possible in present tokamaks. The choice of plasma parameters to satisfy the above goals and conditions therefore depends on a consideration of the operating space available given the uncertainties of extrapolating from today's knowledge.

In summary, these predictions show that a device whose fusion power output is ~500 MW is the minimum size device that can achieve the energy multiplication requirements with reasonable margins. Such a device can satisfy the technical objectives and has the necessary flexibility to accommodate contingencies.

To maintain the programmatic objective, the ITER design includes provisions, wherever it is possible at reasonable cost, to accommodate the likelihood that some of today's predictions will turn out to be different in reality.

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Although it isn't a viable reality quite yet, fusion power appears to be here soon, and with promising results.

[rhoenix]

Why did you put the + in that link? That is just annoying.
And you linked to the site a few paragraphs down anyway.

Call it a brain fart - originally, I was just going to copy and paste an article or three - I put the links in during editing, and forgot to update the original.

The different sorts of methods listed in the site for achieving nuclear fusion intrigued me, as did their projected timeline.

[Einhander Sn0m4n]

Source website: +http://www.iter.org/

Why did you put the + in that link? That is just annoying.
And you linked to the site a few paragraphs down anyway.

I think I'm going to PM my Senator with the suggestion that the rules regarding flashback suppressors on links be amended to prevent their inappropriate or excessive use on links with no evidence of a hostile forum at the target.

[Molyneux]

Something to keep in mind is they have been saying that for 50 years, and have had adequate funding to work on it.

What is "adequate funding"? Since when does any scientific endeavor not have to work with grossly inadequate resources?

[Teleros]

Since when does any scientific endeavor not have to work with grossly inadequate resources?

I'm sure many have managed fine, but it's the principle of thing - never say you've enough cash .