A closed loop tubular discharge assembly for an electrodeless light-emitting device and discharge reactor is disclosed. The discharge assembly comprises one or more tubular segments tubularly connected at their respective ends to form the closed loop tubular assembly, which hermetically encloses an ionizable gas. At least one of the one or more tubular segments forms a non-cylindrical, hollow-shaped tubular segment. In one embodiment, the non-cylindrical, hollow-shaped segment is formed by an internal tube at least partially enclosed within an external tube, forming a hollow-shaped discharge envelope enclosing the ionizable gas there between. When a discharge current circulates in the ionizable gas of the envelope, a hollow-shaped plasma is created in the envelope and surrounds the internal tube. This design has been shown to increase performance and provide several improvements over prior art devices.