Wigner_Seitz_radius¶

plasmapy.formulary.
Wigner_Seitz_radius
(n: Unit("1 / m3")) > Unit("m")¶ Calculate the WignerSeitz radius, which approximates the inter particle spacing. It is the radius of a sphere whose volume is equal to the mean volume per atom in a solid. This parameter is often used to calculate the coupling parameter. When ion density is used, this is the ion sphere radius, i.e., the space occupied by a single ion with no other ions in that space. Higher density means less space for each ion, so the radius is smaller.
Parameters: n (Quantity) – Particle number density.
Returns: radius – The WignerSeitz radius in meters.
Return type: Raises: TypeError
– If argument is not a ~astropy.units.Quantity.UnitConversionError
– If argument is in incorrect units.ValueError
– If argument contains invalid values.
Warns: ~astropy.units.UnitsWarning – If units are not provided, SI units are assumed.
Notes
The WignerSeitz radius approximates the interparticle spacing. It is the radius of a sphere whose volume is equal to the mean volume per atom in a solid:
\[r = \left(\frac{3}{4 \pi n}\right)^{1/3}\]See also
Example
>>> from astropy import units as u >>> Wigner_Seitz_radius(1e29 * u.m**3) <Quantity 1.33650462e10 m>