What does electromagnetic wave literally look like? Some people on the Internet called electromagnetic wave as something that has literally only two dimensions, I think it is because of this over-publicized picture http://hyperphysics.phy-astr.gsu.edu/hbase/emwav.html. Is it true? Personally, I don't think electromagnetic wave is two-dimensional despite most pictures depicted it as a two-dimensional wave. What do you think?
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4$\begingroup$ Can you provide a link to any of these claims? $\endgroup$– Kyle KanosCommented Dec 11, 2018 at 10:54
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$\begingroup$ I can no longer find the link because if memory serves me right that was a year ago, but you can see this link hyperphysics.phy-astr.gsu.edu/hbase/emwav.html . It shows em wave as something that is two dimensional. Does EM wave really looks like that? $\endgroup$– SnoopyKidCommented Dec 11, 2018 at 15:10
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$\begingroup$ Now this appears to be a dupe of physics.stackexchange.com/q/169769/25301, among others $\endgroup$– Kyle KanosCommented Dec 12, 2018 at 2:36
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$\begingroup$ I clicked the link but the answer whether em wave is two dimensional or not can't be found in the link. So the conclusion is an individual electromagnetic wave (if there's such thing as individual em wave) doesn't look like what this link shows researchgate.net/profile/Mohamed_Saleh50/publication/313725653/…, right? $\endgroup$– SnoopyKidCommented Dec 12, 2018 at 5:00
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$\begingroup$ Also this question (with figures): physics.stackexchange.com/questions/402251/… $\endgroup$– user137289Commented Dec 12, 2018 at 8:52
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I disagree with such statements. Electromagnetic waves are four-dimensional phenomena. They also have quite a few degrees of freedom. The k-vector has three dimensions, there are two polarisation and two independent phases.
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$\begingroup$ I see. I think some people called EM wave as something two dimensional because of this over-publicized picture of EM wave hyperphysics.phy-astr.gsu.edu/hbase/emwav.html So, in reality EM wave doesn't even look like that? $\endgroup$ Commented Dec 11, 2018 at 15:12
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$\begingroup$ That picture clearly is three dimensional. It shows a linearly polarised infinite plane wave, for which E and B always point in the same direction, but the wave pervades all of space. Obviously, a wave can only be plane in a finite volume of space-time. $\endgroup$– my2ctsCommented Dec 11, 2018 at 16:46
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$\begingroup$ Sorry for my ignorance but can you show me which part is three dimensional? What I'm seeing is just two dimensional plane. Why E and B always point in the same direction? Is it impossible for E and B pointing to multi different directions? $\endgroup$ Commented Dec 11, 2018 at 19:38
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1$\begingroup$ There are 3 mutually orthogonal axes in the figure. $\endgroup$– my2ctsCommented Dec 12, 2018 at 0:11
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$\begingroup$ The arrows show the direction and intensity of the electric field on the axis indicated by the line. It is easy to misinterpret the figure. $\endgroup$– my2ctsCommented Dec 12, 2018 at 0:17