Maxwell's Equations: Draw State of Polarization & Find B(x,t)

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SUMMARY

The discussion focuses on deriving the magnetic field B(x,t) from the electric field E(x,t) of an electromagnetic wave using Faraday's law. The electric field is defined as E(x,t) = E0( y + e^(i3π/2) z )e^(i(kx-ωt)), indicating circular polarization (anticlockwise) with amplitude E0. Participants clarify the application of the Faraday-Maxwell equation, specifically ∇ x E = -∂B/∂t, to compute the magnetic field. The correct approach involves using the spatial component of the electric field and applying the curl operation to derive B.

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Homework Statement



Draw the state of polarization of the electromagnetic (EM) wave defined by

*****PLEASE NOTE EQUATION SHOWN IN NEXT POST****** (For some reason can't change it in this post...

with Eo real. Use a sentence to describe in words the state of polarization of this EM wave.

Use the differential form of Faraday's law to obtain B(x,t) for the same EM wave


Homework Equations



*****PLEASE NOTE EQUATION SHOWN IN NEXT POST****** (For some reason can't change it in this post...

The Attempt at a Solution



I have done the first part and found the EM wave to be circularly polarized (anticlockwise) with an amplitude of E0

i am unsure how to use faradays law. I tried breaking the LHS of faraday into its respective partial differential vector form, which i am currently working my way through but i am fairly sure it is wrong!

Any ideas on how to apply to get the magnetic field from the electric using faraday-maxwell's law would be greatly appreciated!

Many Thanks
 
Last edited:
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Sorry i copied and pasted the equation and it has come out wrong...

It should read

E(x,t) = Eo( y + e^(i3\Pi/2) z )e^(i(kx-\omegat)) ,


Bold Letters denote unit vectors

Relevant Equations;

\nabla x E = - \partialB / \partial t (Faraday-Maxwell Equation)

Excuse my mistake!
 
Last edited:
Your electric field is given by

<br /> \mathbf{E}=E(x,y,z,t)=E_0\exp[i(kx-\omega t)]\hat{\mathbf{y}}+E_0\exp[i(kx-\omega t)]\exp\left[i\frac{3\pi}{2}\right]\hat{\mathbf{z}}<br />

correct? But we also know \mathbf{E}=Re(\mathbf{E}&#039;\exp[i\omega t]) where \mathbf{E}&#039; is the spatial component of the electric field. Then through Faraday's law,

<br /> \mathbf{B}&#039;=-\frac{1}{i\omega}\nabla\times\mathbf{E}&#039;<br />

You can then solve \mathbf{B}=Re(\mathbf{B}&#039;\exp[i\omega t]).
 
Now that I've had a good night's rest, you can actually ignore the fact that I said the real components of the spatial electric and magnetic components. This would only be true if your original electric field were given by cosine.
 
Thank you, that really helps! I appreciate it!
 

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