These movies show the development of a flame from a pre-chamber. This technology is used in natural-gas engine and the research aims to provide information of the structure of the ignition process. The movies are taken at 5.34kHz and monitor OH* chemilumiscence. The pre-chamber is filled with stoichiometric ethylene-air mixture, it is ignited by a focused 1064nm laser pulse, and the ensuing flame ignites the outer mixture. In one movie, there is fuel in the outer fluid, while in the other there isn't any fuel, demonstrating the jet flame only.