Sodium vapor process is a method of producing light by passing an electric current through a vaporized sodium metal. This process is used in high-pressure sodium (HPS) lamps, which are commonly used for street lighting. The process involves heating the sodium metal to temperatures of around 800°C, which causes it to vaporize. When an electric current is passed through the vaporized sodium, it emits yellow-orange light with a wavelength of 589 nanometers. This light is then focused and directed by a reflector to create the desired lighting effect.