Lundquist number

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In plasma physics, the Lundquist number (denoted by S) is the dimensionless ratio of an Alfvén wave crossing timescale to a diffusion timescale. In SI units, it is given by

,

where L is a typical length scale, μ₀ is the permeability of free space, is the Alfvén speed, and η is the plasma resistivity. High Lundquist numbers indicate highly conducting plasmas, while low Lundquist numbers indicate more resistive plasmas. Laboratory plasma experiments typically have Lundquist numbers between 50 − 10⁸, while in astrophysical situations the Lundquist number can be greater than 10²⁰. Considerations of Lundquist number are especially important in magnetic reconnection.

[edit] References

• Eric Priest, Terry Forbes, Magnetic Reconnection, Cambridge University Press 2000, ISBN 0521481791, contents and sample chapter online