Lundquist number

In plasma physics, the Lundquist number (denoted by $S$ ) is a dimensionless ratio which compares the timescale of an Alfvén wave crossing to the timescale of resistive diffusion. It is a special case of the Magnetic Reynolds number when the Alfvén velocity is the typical velocity scale of the system, and is given by

S={\frac {Lv_{A}}{\eta }},

where $L$ is the typical length scale of the system, $\eta$ is the magnetic diffusivity and $v_{A}$ is the Alfvén velocity of the plasma.

High Lundquist numbers indicate highly conducting plasmas, while low Lundquist numbers indicate more resistive plasmas. Laboratory plasma experiments typically have Lundquist numbers between $10^{2}-10^{8}$ , while in astrophysical situations the Lundquist number can be greater than $10^{{20}}$ . Considerations of Lundquist number are especially important in magnetic reconnection.

References

Priest, Eric; Forbes, Terry (2000), Magnetic Reconnection (PDF), Cambridge University Press, ISBN 0-521-48179-1

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Lundquist number

See also

References