Debye_number
- plasmapy.formulary.dimensionless.Debye_number(T_e: Unit('K'), n_e: Unit('1 / m3'))[source]
Return the number of electrons within a sphere with a radius of the Debye length.
Aliases:
nD_
- Parameters:
- Raises:
astropy.units.UnitConversionError – If either argument is in incorrect units.
ValueError – If either argument contains invalid values.
- Warns:
UnitsWarning
– If units are not provided, SI units are assumed.- Returns:
N_D – Number of electrons within a sphere with a radius of the Debye length.
- Return type:
Notes
The Debye number is the number of electrons contained within a sphere with a radius of a Debye length and is given by
\[N_D = \frac{4π}{3} n_e λ_D^3\]The Debye number is also known as the plasma parameter.
Collective behavior requires \(N_D ≫ 1\).
See also
Examples
>>> import astropy.units as u >>> from astropy.constants.si import m_p, m_e >>> Debye_number(5e6*u.K, 5e9*u.cm**-3) <Quantity 2.17658...e+08>