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Maxwell equations lead to simultaneous perpendicular oscillations of electric field as well as magnetic field with same amplitude and “wavelength”. But, they do not guarantee any propagation of these fields. Based on oscillations of these fields, there is a common perception on propagation of electromagnetic waves as the one given in the link. I never found a reference which provides a practical verification of existence of magnetic field component and electric field component of an electromagnetic wave; in which both components have same amplitude and same wavelength. I like to mention one detail about length/height of amplitudes. When basic units are fixed, then derived units are also fixed and thereby units for amplitudes are also fixed. I did not find a reference for a practical experiment in connection with existence of two components with same wavelength and same amplitude. I like to ask for a reference only for practical experiments. I do not like to know about a practical experiment which considers the “electromagnetic waves” produced by magnetrons, because these waves do not have speed that is equal to speed of light in vacuum, even though these waves may have speed nearly equal to speed of light in vacuum. So, I like to ask for a reference only for electromagnetic waves which have speed exactly equal to the speed of light in vacuum.

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  1. "Maxwell's equations lead to simultaneous perpendicular oscillations of electric field as well as magnetic field with same amplitude and “wavelength”. But, they do not guarantee any propagation of these fields."
  • Wrong. They do.
  1. "I never found a reference which provides a practical verification of existence of magnetic field component and electric field component of an electromagnetic wave; in which both components have same amplitude and same wavelength."
  • Wrong. They they have the same frequency, because they are two aspects of the same entity (two components of the same 4vector).

As to the experimental proof: There is ample evidence of the validity of Maxwell's equations, from :

    • Static electricity experiments (which prove that $\nabla \cdot E\ =\ \rho /\xi_{o}$ is correct)
    • to Magneto-static experiments (or experiments with transformers, or induction ovens, etc.), which prove that $\nabla \wedge B\ =\ \mu_{0} \ (J\ +\ 1/\epsilon_{0\ \ \ \ } dE/dt)$ and $\nabla \wedge E\ =\ -dB/dt$ are correct.
    • To the absence of magnetic monopoles or charges, which prove that $\nabla \cdot B\ =\ 0$
    • To the Michelson and Morley experiment, which measured the speed of light and proved it to be the same regardless of referential.
    • To the existence of radio waves...
    • etc...

So basically, if one admits that Maxwell's formulation is correct, then the math implies that electromagnetic waves:

  1. Exist.
  2. Can propagate (in a vacuum or otherwise).
  3. That they have an E and and B component which are linked by the equations (by their own internal dynamics) and have therefore the same frequency and alternating phases.

... As to the respective amplitudes, it's a matter of conventions. You could take the convention that:

  • $ \epsilon_{0} = \mu_{0} = c = 1 $, if you like.

Last, but not least as for the question in the title: "What is a reference for a practical experiment for existence electric field wave and magnetic field wave in an electromagnetic wave?"

The fact that linear antennas and circular antennas can be used to detect the same radio signal proves that one given electromagnetic wave has both an electric component (detectable by a by linear antenna) and a magnetic component (detectable by a circular antenna), see:

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  • $\begingroup$ Wow @SergeHulne good answer, +1. Only one small nitpick. On the line "To the absence of magnetic monopoles" could you change the period ($\nabla.B$) to \cdot ($\nabla \cdot B$) $\endgroup$ – Dale Apr 21 at 13:19

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