  The flow generated by low-density radiatively driven winds which decouple
their gas and radiation fields is discussed. In particular we concentrate on
flow which is still bound to the star and can therefore reaccrete. The wind
decelerates after decoupling and eventually stalls. A shell of gas is
generated, and we find that this shell is unstable and contracts back to the
star with periods of hours to days.
  We find that the pulsating shells may be difficult to observe, as their
emission is variable and the maximum emission at H-alpha (of ~1% of the
continuum) occurs over a small fraction of the shell cycle.
