  Spherically collapsing cavitation bubbles produce a shock wave followed by a
rebound bubble. Here we present a systematic investigation of the energy
partition between the rebound and the shock. Highly spherical cavitation
bubbles are produced in microgravity, which suppress the buoyant pressure
gradient that otherwise deteriorates the sphericity of the bubbles. We measure
the radius of the rebound bubble and estimate the shock energy as a function of
the initial bubble radius (2-5.6 mm) and the liquid pressure (10-80 kPa). Those
measurements uncover a systematic pressure dependence of the energy partition
between rebound and shock. We demonstrate that these observations agree with a
physical model relying on a first-order approximation of the liquid
compressibility and an adiabatic treatment of the non-condensable gas inside
the bubble. Using this model we find that the energy partition between rebound
and shock is dictated by a single non-dimensional parameter $\xi = \Delta
p\gamma^6/[{p_{g0}}^{1/\gamma} (\rho c^2)^{1-1/\gamma}]$, where $\Delta
p=p_\infty-p_v$ is the driving pressure, $p_{\infty}$ is the static pressure in
the liquid, $p_v$ is the vapor pressure, $p_{g0}$ is the pressure of the
non-condensable gas at the maximal bubble radius, $\gamma$ is the adiabatic
index of the non-condensable gas, $\rho$ is the liquid density, and $c$ is the
speed of sound in the liquid.
