Radiating Charge

Watch Radiating Charge live in the browser

Field lines of an electric charge fan out from a bright point on a dark background. When the charge is jolted the lines kink, and the kinks travel outward as an expanding shell, turning from cool blue to hot orange where the radiation is strong.

The picture follows the Liénard–Wiechert description of a moving charge: news of it travels at the speed of light, so each point in space sees the charge where it was at an earlier, retarded moment. The charge's path is recorded every frame, and every pixel searches that history for its retarded time. It is the construction behind Purcell's and Tsien's textbook drawings of radiation, computed live. In silence, time stands still.

What it reacts to

• Bass: shakes the charge back and forth, so trains of waves roll out along the lines
• Kick drum: jerks the charge and launches a sharp kink; every fourth kick is a hard jerk
• Snare: knocks the charge sideways
• Mids: raise the frequency of the shaking
• Loudness: runs the clock; with no sound the field freezes

Tune

Speed of light sets how fast the kinks travel, Field lines the number of lines, Kick jerk the strength of the jolts, and Field and Radiation the colours of the calm and radiating parts.

Music that suits it

Tracks with punchy, syncopated drums, such as breakbeat or hip-hop, send distinct kinks outward, while sustained bass makes continuous wave trains.

How to play it

Install Deus, play music on Spotify, YouTube Music, Yandex Music or any other tab and click the Deus icon on that tab. Then pick Radiating Charge in the WebGL presets, or press ← → on the page until it comes up.