Wellenradius

Wellenradius is a term used in physics, particularly in German-language texts, to describe the radial extent of a propagating wave from its source. It is commonly interpreted as the radius of the wavefront, i.e., the set of points reached by the wave at a given time, which for a point source in a homogeneous medium is approximately spherical.

In optics, the Wellenradius is tied to the radius of curvature ρ of the wavefront. A perfectly spherical wave produced by an ideal point source has a wavefront whose radius of curvature equals its distance from the source. For non-ideal beams, such as Gaussian beams, ρ varies with propagation distance and relates to how the beam focuses or diverges.

In acoustics and quantum mechanics, the Wellenradius describes the radial extent or localization of the wave or wave packet. It is experimentally accessible through interference and diffraction measurements, by analyzing fringe spacing and wavefront curvature. In many practical problems, the term is used descriptively and its precise meaning can depend on the context, so it is advisable to verify its definition in a given source.

See also: Wavefront, Radius of curvature, Wave packet, Spherical wave, Gaussian beam.