Rotational Instabilities in Post-Collapse Stellar Cores
  A core-collapse supernova might produce large amplitude gravitational waves if, through the collapse process, the inner core can aquire enough rotational energy to become dynamically unstable. In this report I present the results of 3-D numerical simulations of core collapse supernovae. These simulations indicate that for some initial conditions the post-collapse inner core is indeed unstable. However, for the cases considered, the instability does not produce a large gravitational-wave signal. 
David Brown