Plane wave
Type of wave propagating in 3 dimensions / From Wikipedia, the free encyclopedia
In physics, a plane wave is a special case of a wave or field: a physical quantity whose value, at any moment, is constant through any plane that is perpendicular to a fixed direction in space.[1]
For any position in space and any time
, the value of such a field can be written as
where
is a unit-length vector, and
is a function that gives the field's value as dependent on only two real parameters: the time
, and the scalar-valued displacement
of the point
along the direction
. The displacement is constant over each plane perpendicular to
.
The values of the field may be scalars, vectors, or any other physical or mathematical quantity. They can be complex numbers, as in a complex exponential plane wave.
When the values of are vectors, the wave is said to be a longitudinal wave if the vectors are always collinear with the vector
, and a transverse wave if they are always orthogonal (perpendicular) to it.