Abstract: A discharge tube arrangement comprises an excitation device and a discharge tube made of a light-transmissive dielectric material and containing a fill. The excitation device is suitable, when energized with radio frequency (r.f.) power, for exciting surface waves in the discharge tube. The excitation device includes a launcher and a plurality of electrical components associated with the supply of r.f. power to the launcher and constituting at least one of an impedance matching network and a part at least of means to generate r.f. power. This plurality of electrical components is positioned in the launcher between its inner and outer tubes.

Abstract: A discharge tube arrangement includes a discharge tube containing a fill and means for generating a discharge in the fill from a source of radio frequency (r.f.) power. An electrically conductive structure surrounds the discharge tube. The electrically conductive structure is formed of a plurality of waveguides which extend outwardly from the discharge tube. One or more waveguides has a cross-sectional area that increases with separation from the discharge tube. Each waveguide is dimensioned to support the propagation of electromagnetic radiation above a cut-off frequency.