  We explore the low energy dynamics of charge two instantons and dyonic
instantons in SU(2) 5-dimensional Yang-Mills. We make use of the moduli space
approximation and first calculate the moduli space metric for two instantons.
For dyonic instantons the effective action of the moduli space approximation
also includes a potential term which we calculate. Using the ADHM construction
we are able to understand some aspects of the topology and structure of the
moduli space. We find that instantons undergo right angled scattering after a
head on collision and we are able to give an analytic description of this in
terms of a quotient of the moduli space by symmetries of the ADHM data. We also
explore the scattering of instantons and dyonic instantons numerically in a
constrained region of the moduli space. Finally we exhibit some examples of
closed geodesics on the moduli space, and geodesics which hit the moduli space
singularities in finite time.
