# Questions tagged [lienard-wiechert]

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### Derivation of Liénard-Wiechert Potential in quasi-rest reference frame

In electrodynamics, using the Maxwell equation: $\partial_{\mu}F^{\mu\nu}=\frac{4\pi}{c}J^{\nu}$, together with the Lorentz gauge: $\partial^{\mu}A_{\mu}=0$, we can derive the equation for vector ...
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### Where did I misunderstand Lienard-Wiechert?

Here's my problem. Intensity of radiation follows an inverse square law with distance. https://byjus.com/physics/inverse-square-law/ Electromagnetic fields can be derived from the Lienard Wiechert ...
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### Is there anything special about sinusoidal EM waves? How does the strength of a purely sinusoidal EM wave vary with distance from the source?

In this atoms and sporks video, the narrator mentions that not all Electromagnetic (EM) waves have to be sinusoidal. In fact, he gives a nice animation of such a case at 16:42. He talks about a ...
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### Do the Lienard Wiechert Potentials satisfy the wave equation?

The Lienard Wiechert potential (leaving out the vector potential for simplicity), $$\left.\phi(\vec{r},t)=\frac{e}{4\pi\epsilon_0R\,(1-\hat{n}\cdot\vec{\beta})} \right|_{t'=t_{\rm ret}},$$ where the ...
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### Gauge invariant Green's function for electrodynamics

Varying the electromagnetic action \begin{equation} S=-m c \int d s\left(\dot{z}^{2}\right)^{\frac{1}{2}}-\frac{e}{c} \int d s A_{\mu} \dot{z}^{\mu}-\frac{1}{16 \pi c} \int d^{4} x F_{\mu \nu} F^{\mu \...
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### Is the Liénard-Wiechert electric field conservative?

I know that an accelerated charge should emit an e.m. field and loose energy. Therefore, the Liénard-Wiechert (L.W.) electric field of an accelerated charge should be non-conservative. But I checked ...
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### Falling charged objects: energy conservation paradox?

Imagine that we start with two oppositely charged objects on the ground, separated by a distance $d$, with charges $+q$, $-q$ and masses $m$. We raise them both up to a height $h$. In doing so we ...
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### Energy conservation in electrodynamic system

Consider two charged particles initially at rest in the configuration below. Let us assume the following: Starting at time $t=0$, we apply a constant force $f$ to the the bottom particle so that it ...