# inertial_length¶

plasmapy.physics.parameters.inertial_length(n, particle='e-')

Calculate the particle inertial length. At this length, the Hall effect becomes important.

Parameters: n (Quantity) – Particle number density in units convertible to m**-3. particle (str, optional) – Representation of the particle species (e.g., ‘p’ for protons, ‘D+’ for deuterium, or ‘He-4 +1’ for singly ionized helium-4), which defaults to electrons. If no charge state information is provided, then the particles are assumed to be singly charged. d – Particles inertial length in meters. Quantity TypeError – If n not a Quantity or particle is not a string. UnitConversionError – If n is not in units of a number density. ValueError – The particle density does not have an appropriate value. ~astropy.units.UnitsWarning – If units are not provided, SI units are assumed

Notes

The particle inertial length is also known as an particle skin depth and is given by:

$d = \frac{c}{\omega_{pi}}$

Example

>>> from astropy import units as u
>>> inertial_length(5*u.m**-3, particle='He+')
<Quantity 2.02985802e+08 m>
>>> inertial_length(5*u.m**-3)
<Quantity 2376534.75601976 m>