EL wire

Electroluminescent (EL) wire is a thin copper wire coated in phosphor that produces light when an alternating current is applied to it. The light emitted by EL wire is similar to a neon light or a very bright glowstick.
EL wire is covered with a protective PVC sheath and sometimes a colored plastic shell to make it appear another color. It appears similar to common telephone wire and emits light along its entire length without any heat radiation.