If a pulsed, radially symmetric planar source imbedded in a rigid baffle of infinite extent is described by a normal surface acceleration history of the forman = δ(t + r/vs), whereris radial surface distance from the source center,v, is the speed of uniform radial contraction, and the motion proceeds fromr=ator= 0, then convergent and intersecting wave fronts can be produced in the nearfield of this source. Fields from this source have been calculated using techniques described previously [S. I. Warshaw, J. Acoust. Soc. Am. Suppl. 177, S60 (1985); and79, S90 (1986); Proc. 12th ICA, Toronto, 1986] in the time domain. The calculation technique will be reviewed briefly and compared for contracting and expanding ring sources. Details of the time‐evolving two‐dimensional wave field will be presented in the form of contours of constant acoustic amplitude calculated at different times from source onset to propagation past the convergence zone. The various dynamically changing wave front patterns will be indicated and discussed. [Work supported by U.S. Department of Energy.]