Flare (electronic warfare)
In electronic warfare, which covers the entire electromagnetic spectrum including infrared light, a flare (electronic warfare) is an expendable cartridge that, once leaving the launcher, burns brightly. Its principle is that it will be a more attractive source of infrared light to a heat-seeking missile.
While they can be launched manually, military platform usually dispense flares from magazine-loaded, increasingly intelligent expendable coutermeasures devices such as the AN/ALE-47. Such dispensers usually can release chaff (electronic warfare) in a cartridge with the same form factor as the flares, and even more expendable cartridges, such as radar jammers and intelligence sensors, are in the same package.
Flares may have to evolve beyond being a simple heat source, when missiles, which previously homed on the brightest wide-spectrum source of infrared light, now look for multiple infrared wavelengths, or, as with the FIM-92 Stinger, for a combination of infrared and ultraviolet energy. While the first such flares burned magnesium, most modern sensors would ignore such a primitive deception.