Questions tagged [poynting-vector]
The directional energy flux of an electromagnetic field. In conjunction with Poynting's theorem and the continuity equation, it used to express the conservation of electromagnetic energy, and to calculate the power flow in electric and magnetic fields.
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Why is the Poynting flux not conserved across the interface between two conducting materials?
This question is part of my attempt to use an answer to another question I've posted on this site.
If I have two materials with complex indices of refraction, $\widetilde{n}_0$ and $\widetilde{n}_1$, ...
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J. J. Thomson's "on momentum in the electric field": can it be true physically?
J. J. Thomson imagined a physical system consisting of one electric field source (charge $q$ or else) and one magnetic field source (magnetic monopole $g$ or maybe magnet or something else), with $q$ ...
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General formula of Poynting vector
My question regards the actual definition of the Poynting vector. Although in vacuum and linear materials we can write $\textbf B=\mu \mathbf H$ and so there is no doubt that $\mathbf S=\frac{\mathbf ...
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Trouble deducing a dipole's scattering cross section (optics)
(I've already visited this post but it begins precisely with the formula I'm trying to derive). I'm trying to deduce the scattering cross section for an electron bound to a nucleus in the far field:
$$...
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Poynting's theorem in dispersive media
I am reading Jackson's Classical Electrodynamics (3rd ed) Section 6.8 on Poynting's Theorem in linear dispersive media with losses. From what I understand, in the last equation, the term $[-i\omega \...
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Dot product in optics
(Before marking this question as a duplicate, please consider I've read this post but it I didn't find the answers to it quite satisfactory regarding my doubt).
I'm trying to derive the expression of ...
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Confusion in Poynting's theorem
The total force on a charge is equal to $\mathbf {F}=q\mathbf {(E+ v×B)}$ where everything have their usual meanings . We can say that:
$$dW= \mathbf {F\cdot dl} = {\mathbf{F}\cdot \frac{d \mathbf{l} ...
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Poynting's theorem and continuity equation
I have recently come to realise that many of the most fundamental theorems can be reduced to a continuity equation. Doing some research on the topic of said equations, I have found out they have ...
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Showing that Poynting’s theorem preserved with Proca Lagrangian
The Proca Lagrangian is
$$\mathcal{L}=-\frac{1}{4\mu_0}F_{\mu\nu}F^{\mu\nu}-\frac{1}{2\mu_0\Lambda^2}A_{\mu}A^{\mu}+A_{\mu}J^{\mu}$$
Where $\Lambda=\frac{\hbar}{m_{\gamma}c^2}$.
The symmetric energy-...
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Energy of Monochromatic Beam of Light
A monochromatic beam of light has energy
$$ E_{\text{beam}} = N \hbar \omega, $$
$ N $ being the number of photons in the beam and $ \omega $ their frequency.
Another way to evaluate this energy is ...
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How can I calculate the energy of Electromagnetic wave for specific range of wavelength?
I have captured a wide bandwidth of electromagnetic waves (E and B fields) in the simulation. I would like to calculate the energy within a specific bandwidth. How can this be achieved? Which method ...
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Is power through a surface Lorentz invariant?
I am trying to solve this problem from Griffiths, but my point is not really to ask the answer of this problem :
A point charge $q$ is moving velocity $v$ parallel to $x$ axis. determine the total ...
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How to model power transmission along a power transmission line?
I am a bit confused on this matter.
Suppose we have an alternating current power source. One can transmit electric power two ways
Through radiation, e.g., via an antenna.
Through a transmission (...
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Poynting vector and plane waves
Suppose the electromagnetic field at a point is a superposition to two plane waves $(\vec E_1, \vec H_1)$ and $(\vec E_2, \vec H_2)$. If the two plane-waves have different frequencies, the (time-...
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Showing that the power is $P=UI$ using the Poynting vector
If I have a circuit with a resistor I want to show that the power delivered to the resistor is UI using Poynting vector. To do this I must integrate the pointing vector over a surface that contains ...
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