Electromagnetic wave and polarization
The fields in an electromagnetic wave moving along the X axis are
E
= Ey cos(kx-ωt) j + Ez
cos(kx-ωt+δ) k
B = Bz
cos(kx-ωt) k - By cos(kx-ωt+δ)
j = (c×E)/c2
where c
= c i, Bz = Ey/c
and By = Ez/c. Units are chosen
so that c = 1. Below you can choose the amplitudes Ey
and Ez, as well as the wavelength λ = 2π/k
and the relative phase δ.
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The point of view of the three-dimensional projection can be changed
with the cursors or the mouse.
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The whole image can be moved with the mouse while pressing Ctrl.
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To change the zoom in the projection, press Shift when moving
up or down the mouse pointer.
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Put the mouse pointer over an element to get information about it.
Activities
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Familiarize yourself with the elements in the simulation: you may
display at the same or different times the total and partial electric
and magnetic fields. It is also possible to display the evolution
(and, optionally, the trajectory) of the electric field at a point you
may select with the mouse or by entering its x
coordinate.
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Discuss in which cases the total wave will be polarized linearly. Use
the simulation to show it.
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Are you able to get circular polarization?
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And elliptic polarization?
This is an English translation of the Basque original for a course
on mechanics, oscillations and waves.
It requires Java
1.5 or newer and was created by Juan
M. Aguirregabiria, based on the simulation by Fu-Kwun
Hwang, with Easy Java
Simulations (Ejs) by Francisco
Esquembre. I thank Wolfgang Christian and Francisco Esquembre for
their help.