An electromagnetic wave is said to have circular polarization when its electric and magnetic fields rotate continuously around the beam axis during the propagation.

This SAM is directed along the beam axis (parallel if positive, antiparallel if negative).

The shroud shields the antenna from radiation from angles outside the main beam axis, reducing the sidelobes.

Compressive and tensile forces develop in the direction of the beam axis under bending loads.

The gradient force thus pulls object onto the beam axis.

The highest stretching forces can be found on the beam axis, where the light intensity is highest and the rays incide at right angle.

The intensity of such scattering increases when these beams are viewed from angles near the beam axis.

The difference in the rapidity of two particles is independent of Lorentz boosts along the beam axis.

Principal tensile fibres are oriented in the beam longitudinal axis, similar to its internal flexural steel reinforcement.

Gases are introduced under pressure around the lens to cool it before passing out along the beam axis.