inertial_length
- plasmapy.formulary.lengths.inertial_length(
- n: Quantity,
- particle: str | int | integer | Particle | CustomParticle | Quantity,
- *,
- mass_numb: int | None = None,
- Z: float | None = None,
Calculate a charged particle’s inertial length.
The inertial length of a particle of species \(s\) is given by
\[d = \frac{c}{ω_{ps}}\]The inertial length is the characteristic length scale for a particle to be accelerated in a plasma. The Hall effect becomes important on length scales shorter than the ion inertial length.
Aliases:
cwp_
- Parameters:
n (
Quantity
) – Particle number density in units convertible to m-3.particle (particle-like) – Representation of the particle species (e.g., ‘p+’ for protons, ‘D+’ for deuterium, or ‘He-4 +1’ for singly ionized helium-4).
mass_numb (integer, keyword-only, optional) – The mass number, if not provided in
particle
.Z (real number, keyword-only, optional) – The charge number, if not provided in
particle
.
- Returns:
d – The particle’s inertial length in meters.
- Return type:
- Raises:
TypeError – If
n
is not aQuantity
orparticle
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.
- Warns:
UnitsWarning
– If units are not provided and SI units are assumed.
Notes
The inertial length is also known as the skin depth.
Examples
>>> import astropy.units as u >>> inertial_length(5 * u.m**-3, "He+") <Quantity 2.02985...e+08 m> >>> inertial_length(5 * u.m**-3, "e-") <Quantity 2376534.75... m>