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An Electromagnetic Plane Wave
Goals
The Illustrations
A Traditional View of an Electromagnetic Plane Wave
Two Three-Dimensional Views of an Electromagnetic Plane Wave
A Traditional View of an Electromagnetic Plane Wave
- The velocity of the wave is in the x direction.
- The electric field (E) points in the y direction (+ or -).
- The magnetic field (B) points in the z direction (+ or -).
- The lengths of the E and B vectors represent their strengths. At any instant of time, they both vary along the x axis, but they are constant in any y-z plane
A Three-Dimensional View of an Electromagnetic Plane Wave
Perspective View
- As in the traditional view, the lengths of the vectors represent their strengths at selected points along the x axis.
- The electric field vectors are in red with the backs of their arrowheads in orange.
- The magnetic field vectors are in blue with the backs of their arrowheads in magenta
- The whole scene is only an instant of time. As time flows, all vectors change in size. This is demonstrated in the animation.
Side View
Top View
An Extended Three-Dimensional View of an Electromagnetic Plane Wave (a Vector Forest)
- In the previous set of images, each individual vector only represents the strength of the field at a specific point along the x axis. Actually, in a plane wave, there is a whole plane of vectors of the same strength extending throughout the y-z plane. Part of the plane of E and B vectors illustrated here for just one y-z plane.
- These images show a model of the whole group of extended plane sections from different points of view. The perspective views are rather crowded with information, perhaps better appreciated in the animation.
- The E (red) and B (blue) vectors are only shown at selected points in each plane section. They actually exist uniformly throughout each plane.
- To limit the clutter a little bit, the axes have been removed, but green lines have been drawn in the x direction to indicate the corners of the y-z planes.
- The model represents an instant of time. The animation flys around the model, but it is held static in time.
- This model attempts to illustrate the same concepts as the previous one, but with less clutter. Only the electric field vectors are shown and their strength is indicated by their opacity rather than their length. Thus, the weaker fields are shown as more transparent, not as shorter. You can also see an animated version.
