Tracing back an electromagnetic wave to its source

[andresB]

Suppose you have a solution to the Maxwell's equations in vacuum, and now you want to find what kind of charge/current system create the wave in the first place, can this be done?

 

[ZapperZ]

Suppose you have a solution to the Maxwell's equations in vacuum, and now you want to find what kind of charge/current system create the wave in the first place, can this be done?

You have not given sufficient information. All you've given is that the medium is a vacuum. You have not described the boundary conditions, and the relative size of the EM wavelengths to any confined space (i.e. if this is in a waveguide).

Zz.

 

[andresB]

I only have a vector function E and a vector function B that satisfy all the source-free Maxwell's equations.

 

[andresB]

And if that is not enough, then how much more information is required?

 

[Dale]

If it is source-free/vacuum then by definition there are no charges or currents.

 

[ZapperZ]

And if that is not enough, then how much more information is required?

I've just told you! The nature of the boundary conditions! Are these E and B fields solved in a waveguide? In free space? And if there is a boundary, what kind of a boundary is it?

For example, if you are given a standing wave in a waveguide, then I don't see how you can have the ability to trace where the "source" is.

Zz.

 

[marcusl]

If you know the fields everywhere on a closed surface that surrounds the source, then you can solve for an equivalent multipole source that produces the same fields as the real source.