Plasma parameter: Difference between revisions

Revision as of 02:11, 25 March 2009

Revision as of 02:11, 25 March 2009

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The ''plasma parameter'' is a dimensionless number, denoted by capital Lambda, Λ. The plasma parameter is usually interpreted to be the argument of the Coulomb logarithm, which is the ratio of the maximum impact parameter to the classical distance of closest approach in [[Coulomb_collision |Coulomb scattering]]. In this case, the plasma parameter is given by<ref>Chen, F.F., Introduction to Plasma Physics and Controlled Fusion, (Springer, New York, 2006)</ref>:

:<math> \Lambda = 124\pi n \lambda_D^3 </math>

where

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:<math> N_D = \frac {4\pi}{3} n \lambda_D^3 </math>

Since these two definitions differ only by a factor of ninethree, they are frequently used interchangeably.

Often the factor of <math>4\pi/3</math> is dropped. When the Debye length is given by <math> \lambda_D = \sqrt{\frac{\epsilon_0 k T_e}{n_e q_e^2}}</math>, the plasma parameter is given by<ref>Miyamoto, K., Fundamentals of Plasma Physics and Controlled Fusion, (Iwanami, Tokyo, 1997)</ref>