plasmapy.diagnostics.langmuir.get_electron_density_LM(electron_saturation_current: Quantity, T_e: Quantity, probe_area: Quantity) Quantity[source]

Implement the Langmuir-Mottley (LM) method of obtaining the electron density.

  • electron_saturation_current (Quantity) – The electron saturation current in units convertible to A.

  • T_e (Quantity) – The electron temperature in units convertible to eV.

  • probe_area (Quantity) – The area of the probe exposed to plasma in units convertible to m2.


n_e – Estimate of the electron density in units convertible to m-3.

Return type:



The method implemented in this function obtains the electron density from the electron saturation current density, assuming a low plasma density. The electron saturation current is given by

\[I_{es} = \frac{1}{4} e n_e A_p \sqrt{\frac{8 T_e}{\pi m_e}}.\]

Please note that the electron saturation current density is a hard parameter to acquire and it is usually better to measure the ion density, which should be identical to the electron density in quasineutral plasmas.