Poynting Vector: Energy Flow in Electromagnetic Fields

Electromagnetic energy does not travel where intuition expects it to. This simulator renders the Poynting vector S = (1/μ₀)E×B directly in 3D across three canonical geometries: a charging parallel-plate capacitor, where energy streams in radially from the surrounding field rather than along a wire; a current-carrying resistor, where the classic paradox shows power entering through the field around the conductor and being dissipated as Joule heat; and a propagating plane wave, where S marches steadily forward as E and B oscillate together. Live vector fields for E (blue), B (green) and S (orange) update every frame from the real field equations — Ampere–Maxwell's law for the displacement current, Ampère's law for the wire, and the wave equation for the propagating fields — with numeric readouts at a fixed probe point so you can see cause and effect in real numbers, not just arrows.