The line will not support a true TEM wave; at non-zero frequencies, both the E and H fields will have longitudinal components (a hybrid mode).
The longitudinal components are small however, and so the dominant mode is referred to as quasi-TEM.
A terminology often used in physics refers to the curl-free component of a vector field as the longitudinal component and the divergence-free component as the transverse component.
Some magnetographs can only measure the component of the magnetic field along the line of sight from the observer to the source (the field's "longitudinal" component).
In 1817, Young had proposed a small transverse component to light, while yet retaining a far larger longitudinal component.
However, the longitudinal component is merely unphysical gauge.
MGRS longitudinal component, with sites in the following locations:
Electric field lines for this [TM] mode have a longitudinal component and require line lengths of a half-wavelength or longer.
The average value of the longitudinal components of these instantaneous forces is called the ship's ice resistance.
Loading points on a tower naturally encompasses longitudinal, transverse and vertical components, either as individual or a combined resultant load.