Lundquist number explained
In plasma physics, the Lundquist number (denoted by
) 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
where
is the typical length scale of the system,
is the
magnetic diffusivity and
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
, while in astrophysical situations the Lundquist number can be greater than
. Considerations of Lundquist number are especially important in
magnetic reconnection.
See also
