Plasma parameters: Difference between revisions

Revision as of 10:24, 1 December 2023

Revision as of 10:32, 1 December 2023

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{{Short description|Characteristic values of a plasma}}

{{Distinguish|text=the [[plasma parameter]]}}

[[Image:Magnetic rope.svg|thumb|300px|The complex self-constricting magnetic field lines and current paths in a [[Birkeland current]] that may develop in a plasma (''[https://history.nasa.gov/SP-345/ch15.htm#250 Evolution of the Solar System]'', 1976) ]]

'''Plasma parameters''' define various characteristics of a [[Plasma (physics)|plasma]], an electrically conductive collection of [[charged particle]]s that responds ''collectively'' to [[electromagnetic force]]s. Plasma typically takes the form of neutral gas-like clouds or charged [[ion beam]]s, but may also include dust and grains.<ref>Peratt, Anthony, ''Physics of the Plasma Universe'' (1992);</ref> The behaviour of such particle systems can be studied statistically.<ref>Parks, George K., ''Physics of Space Plasmas'' (2004, 2nd Ed.)</ref>

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=== Dimensionless ===

[[Image:fusor running.jpg|thumb|right|300px|A 'sun in a test tube'. The [[Farnsworth-Hirsch Fusor]] during operation in so called "star mode" characterized by "rays" of glowing plasma which appear to emanate from the gaps in the inner grid.]]

* number of particles in a Debye sphere <math display="block">\left(\frac{4\pi}{3}\right)n\lambda_D^3 \approx 1.72 \times 10^9\,\left(\frac{T^3}{n}\right)^\frac{1}{2}</math>

* Alfvén speed to speed of light ratio <math display="block">\frac{v_A}{c} \approx 7.28\,\frac{B}{\left(\mu n_i\right)^\frac{1}{2}}</math>