Vecteur de Poynting en 3D
Energy in an electromagnetic wave does not travel in the wires — it travels in the fields. This 3D visualisation draws the Poynting vector alongside the electric and magnetic fields, showing the direction and rate of energy flow.
Comment utiliser cette simulation
- Rotate the 3D scene to view the vector triad from any angle
- Adjust the field amplitudes and the wave frequency
- Toggle between instantaneous and time-averaged flow
Ce qu’il faut observer
- S, E and B form a mutually perpendicular right-handed set
- Energy flow peaks when both fields peak and drops to zero when they cross zero
- Reversing either field reverses the direction of energy transport
La physique derrière
The Poynting vector S = E × B/μ₀ gives the energy flux, in watts per square metre, carried by an electromagnetic field. Its direction is perpendicular to both E and B, which for a plane wave means energy travels in the propagation direction. Its magnitude oscillates at twice the wave frequency, and the time-averaged value is the intensity.