Visualizing the Electric Field Around a Moving Charge

A short tour of field-vector animations and the law behind them.

Canal
3Blue1Brown
Publicado
26 ene 2024
Vídeo
1:00
Lectura
1 min
Diapositivas
2
Original
inglés
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RESUMEN

En 30 segundos

3Blue1Brown shares simulations made for a longer video about light, explains electric field vectors and contrasts a full three-dimensional view with a planar slice. The simulation uses an intermediate law derived from Maxwell’s equations.

  1. 1Field as vectorsEach point has a vector describing force per unit charge.
  2. 2A planar sliceA two-dimensional slice can make a dense three-dimensional field easier to see.
  3. 3A derived lawThe simulation uses an intermediate law derived from Maxwell’s equations.

Conclusiones

  1. Each point has a vector describing force per unit charge.
  2. A two-dimensional slice can make a dense three-dimensional field easier to see.
  3. The simulation uses an intermediate law derived from Maxwell’s equations.
TEXTO COMPLETO

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01

A moving charge and its field

Each point has a vector describing force per unit charge.

I recently had fun making simulations of how an electric field responds to a moving charge. They were created for a longer video on the fundamentals of light; here I share some of the resulting animations.

A three-dimensional electric field
DIAPOSITIVA 1 / 2A three-dimensional electric fieldArrows depict field vectors around the moving charge.

The full electric field is three-dimensional. It associates a vector with each point in space, indicating the force that would act on a unit charge placed there.

02

Slices and the simulation law

A two-dimensional slice can make a dense three-dimensional field easier to see. The simulation uses an intermediate law derived from Maxwell’s equations.

Three-dimensional fields are interesting to look at but can be visually busy, so it is often easier to show a slice, such as the xy plane.

A derived field law
DIAPOSITIVA 2 / 2A derived field lawThe animation displays the intermediate equation referenced by the presenter.

In the main video I discuss the law used for these simulations. Rather than directly coding Maxwell’s equations, I use an intermediate law derived from them, which I find easier to understand for making animations and for students.

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