Convective arc stabilization by lamp rotation

Claim 1

In combination with a constricted arc-discharge device, wherEin during normal operation the constricted arc-discharge will bow outward toward the wall of said device unless said bowing is controlled, the improved device and means for controlling said bowing, comprising: a. a generally tubular, linearly extending, radiation transmissive arc-tube with conductive lead-ins sealed through opposite ends thereof, and wherein the interior wall of said arc-tube has a plurality of inwardly projecting portions which spiral about the longitudinal axis of said arc-tube from one end portion to the other end of the arc-tube; b. electrodes supported by said lead-ins and disposed within said arc-tube; c. a discharge sustaining filling contained within said arctube, which during operation forms a constricted arc-discharge directed between said electrodes; and d. means for rotating the operative arc-tube about its longitudinal axis in the same direction of the advancing spiral of said projecting portions of said arc-tube interior wall, whereby said constrictive arc-discharge is maintained proximate said longitudinal axis.