thermal_speed_coefficients

plasmapy.formulary.speeds.thermal_speed_coefficients(method: str, ndim: int) float

Get the thermal speed coefficient corresponding to the desired thermal speed definition.

See the thermal_speed Notes section for further details of the various thermal speed definitions.

Parameters
  • method (str) – Method to be used for calculating the thermal speed. Valid values are "most_probable", "rms", "mean_magnitude", and "nrl".

  • ndim (int) – Dimensionality (1D, 2D, 3D) of space in which to calculate thermal speed. Valid values are 1, 2, or 3.

Raises

ValueError – If method or ndim are not a valid value.

Notes

For a detailed explanation of the different coefficients used to calculate the thermal speed, then look to the Notes section for thermal_speed. The possible return values are listed the following table:

Thermal speed \(v_{th}\) coefficients.

method

ndim

1

2

3

"most_probable"

\[0\]
\[1\]
\[\sqrt{2}\]

"rms"

\[1\]
\[\sqrt{2}\]
\[\sqrt{3}\]

"mean_magnitude"

\[\sqrt{2/π}\]
\[\sqrt{π/2}\]
\[\sqrt{8/π}\]

"nrl"

\[1\]

Examples

>>> thermal_speed_coefficients(method="most_probable", ndim=3)
1.414213...