Talk:Plasma scaling
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In the section Cosmic application what does this sentence refer to: The consequence of this is that charged particles moving in very highly magnetised space
plasmas, are somewhat different to what is seen in the laboratory
I think this refers to magnetic fields in space being significantly greater than that which can be reproduced in the laboratory. --Iantresman 10:59, 21 December 2005 (UTC)
In the section Dimensionless parameters in tokamaks what are these parameters: The remaining (dimensional) parameters can be taken to be n, T, B, and R.
I find the subject of this article highly interesting, but it is badly written; I hope someone would improve it to the point of a stand-alone encyclopedia article. --DelftUser 19:34, 14 December 2005 (UTC)
[edit] Dimensinos of parameters...
In base dimensions the parameters are:
Particle density n: has dimension 1/length3
The temperature T: has dimension thermodynamic_temperature
The magnetic field B: has dimension mass/(electric_current*time2)
- β ~ nTB -2
There is no way that β has dimension 1. --DelftUser 19:07, 20 December 2005 (UTC)
- The above expression only gives the scaling. In SI units the full expression is
.
- To sort out the dimensions, remember that
,
- so B/μ has dimensions of charge/length/time, and
,
- so B has dimensions of mass/charge/time (in agreement with your expression). Together this gives for B2/2μ0 dimensions of mass/length/time2. Since kBT is an energy (mass*length2/time2), nkBT also has dimensions of mass/length/time2. Therefore β is dimensionless. --Art Carlson 08:56, 21 December 2005 (UTC)
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- Thanks. Is there an article in Wikipedia where β, and the other dimensionless parameters, are defined? If not could you consider adding the definitions to the article. --DelftUser 18:35, 21 December 2005 (UTC)
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- Plasma (physics)#Dimensionless --Art Carlson 20:42, 21 December 2005 (UTC)
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