  We explored the dynamics of how a Bose-Einstein condensate collapses and
subsequently explodes when the balance of forces governing the size and shape
of the condensate is suddenly altered. A condensate's equilibrium size and
shape is strongly affected by the inter-atomic interactions. Our ability to
induce a collapse by switching the interactions from repulsive to attractive by
tuning an externally-applied magnetic field yields a wealth of detailed
information on the violent collapse process. We observe anisotropic atom bursts
that explode from the condensate, atoms leaving the condensate in undetected
forms, spikes appearing in the condensate wave function, and oscillating
remnant condensates that survive the collapse. These all have curious
dependencies on time, the strength of the interaction, and the number of
condensate atoms. Although ours would seem to be a simple well-characterized
system, our measurements reveal many interesting phenomena that challenge
theoretical models.
