plasmapy.formulary.frequencies.plasma_frequency_lite(n: Real, mass: Real, z_mean: Real, to_hz: bool = False) Real

The lite-function for plasma_frequency. Performs the same plasma frequency calculation as plasma_frequency, but is intended for computational use and, thus, has all data conditioning safeguards removed.

  • n (Real) – Particle number density, in units of m-3.

  • mass (Real) – Mass of the particle, in units of kg.

  • z_mean (Real) – The average ionization (arithmetic mean) for the particle species in the plasma. For example, a proton would have a value of z_mean=1.

  • to_hz (bool) – (Default False) Set True to apply the factor of \(1/2π\) and return a value in units of Hz.


wp – The particle plasma frequency in radians per second. Setting keyword to_hz=True will apply the factor of \(1/2π\) and yield a value in Hz.

Return type



The particle plasma frequency is

\[ω_{p} = Z |e| \sqrt{\frac{n}{\epsilon_0 m}}\]

where \(m\) is the mass of the particle, \(e\) is the fundamental unit of charge, \(Z\) is the average charge state z_mean of the particle species, \(n\) is the particle number density. This form of the plasma frequency has units of radians / s, but when using the to_hz keyword a factor of \(1/2π\) will be applied to give a value in Hz.


>>> from plasmapy.particles import Particle
>>> mass = Particle("p").mass.value
>>> plasma_frequency_lite(n=1e19, mass=mass, z_mean=1)
>>> plasma_frequency_lite(n=1e19, mass=mass, z_mean=1, to_hz=True)