Wikipedia:Today's second feature/October 1, 2005

Today's featured picture

Plasma lamp electrode and plasma stream

The central electrode of a plasma lamp, showing a glowing blue plasma streaming upwards. The colors are a result of the radiative recombination of electrons and ions and the relaxation of electrons in excited states back to lower energy states. These processes emit light in a spectrum characteristic of the gas being excited.

Photo credit: PiccoloNamek