Thomson cross section for low-energy scattering

thomsonCrossSection is the classical cross section for scattering electromagnetic radiation by a free electron at low photon energy.

Use

It provides a reference area in plasma and astrophysical scattering estimates. It depends on the electronMass, elementaryCharge, and electromagnetic constants.

Caveats

It applies in the classical, low-energy limit. At high photon energies, quantum Compton scattering is required. Treat a cross section as area, not a geometric particle size; use multiply with number density and path length only in the appropriate model.

Use Thomson Cross Section in a calculation

Enter thomsonCrossSection on a calculator line to see its built-in value, or place the name inside a longer expression. Keep any displayed unit attached when converting or combining physical quantities, and check that every other value uses a compatible dimension.

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