A system for controlling convective flow in a light-sustained plasma includes an illumination source configured to generate illumination, a plasma cell including a bulb for containing a volume of gas, a collector element arranged to focus illumination from the illumination source into the volume of gas in order to generate a plasma within the volume of gas contained within the bulb. Further, the plasma cell is disposed within a concave region of the collector element, where the collector element includes an opening for propagating a portion of a plume of the plasma to a region external to the concave region of the collect element.