Debye_length¶
-
plasmapy.formulary.parameters.
Debye_length
(T_e: Unit("K"), n_e: Unit("1 / m3")) -> Unit("m")¶ - Calculate the characteristic decay length for electric fields,
- due to charge screening.
Aliases:
lambdaD_
Parameters: Returns: lambda_D – The Debye length in meters
Return type: Raises: TypeError
– If either argument is not aQuantity
UnitConversionError
– If either argument is in incorrect unitsValueError
– If either argument contains invalid values
Warns: ~astropy.units.UnitsWarning – If units are not provided, SI units are assumed
Notes
The Debye length is the exponential scale length for charge screening and is given by
\[\lambda_D = \sqrt{\frac{\epsilon_0 k_b T_e}{n_e e^2}}\]for an electron plasma with nearly stationary ions.
The electrical potential will drop by a factor of 1/e every Debye length.
Plasmas will generally be quasineutral on length scales significantly larger than the Debye length.
See also
Example
>>> from astropy import units as u >>> Debye_length(5e6*u.K, 5e15*u.m**-3) <Quantity 0.002182... m>