convective plume

A buoyant jet in which the buoyancy is supplied steadily from a point source; the buoyant region is continuous.

This is to be distinguished from a thermal, which is a discrete buoyant element in which the buoyancy is confined to a limited volume of fluid. A chimney plume is usually a convective plume.
See coherent structures;
compare coning, fanning, lofting, looping.
Emanuel, K. A. 1984. Atmospheric Convection. Oxford University Press, . p. 58.

1. In general, mass motions within a fluid resulting in transport and mixing of the properties of that fluid.