Abstract: A generator including a source of electric energy connected to means for generating sparks between the electrodes of an ignition spark plug, is characterized in that it comprises a first power portion including first means forming a capacitor for storing energy in series with first means forming a diode, wherein the first means forming a capacitor are also connected to the ignition spark plug through a gas spark gap and at least one second triggering portion including second means forming an energy storage capacitor in series with second means forming a diode, wherein the second means forming a capacitor are connected through at least one controlled semiconductor switching unit, to a primary winding of a voltage step-up transformer for which one secondary winding is connected in series with the gas spark gap between the first means forming a capacitor and the ignition spark plug.

Abstract: A device is provided that includes an optical fiber and an assembly illuminating the optical fiber capable of illuminating the optical fiber at an upstream end. The optical fiber includes a hollow core and an anti-resonant annular cladding arranged around the hollow core. The illuminating assembly generates a focused beam of Airy spot shape for injection into the input of the optical fiber.

Abstract: Process for the preparation of a ceramic wherein: 50% to 75% by weight of a compound intended to form a conductive phase, and 25% to 50% by weight of one or more materials allowing the formation of insulating phases composed of silicon nitride and modified silicon oxynitride are mixed in a receptacle containing a liquid after a thermal treatment leading to sintering of the ceramic; this mixture is subjected to grinding, drying and sieving operations; this mixture is pressed; and this mixture is sintered so as to obtain a ceramic with a porosity of between 0 and 30%. The sintering is carried out under a pressure of at least 50 bar of a gas which is inert towards the constituents of the mixture. Ceramic thus obtained and spark plug comprising it.