# Coulomb_cross_section

plasmapy.formulary.collisions.coulomb.Coulomb_cross_section(impact_param: Unit('m'))

Cross-section for a large angle Coulomb collision.

Parameters

impact_param (Quantity) – Impact parameter for the collision.

Returns

sigma – The Coulomb collision cross section area.

Return type

Quantity

Notes

The collisional cross-section for a 90° Coulomb collision is obtained by

$σ = π (2 * ρ_⟂)^2$

where $$ρ_⟂$$ is the distance of the closest approach for a 90° Coulomb collision. This function is a generalization of that calculation. Please note that it is not guaranteed to return the correct results for small angle collisions.

Examples

>>> Coulomb_cross_section(7e-10*u.m)
<Quantity 6.157...e-18 m2>
>>> Coulomb_cross_section(0.5*u.m)
<Quantity 3.141... m2>