  Under suitable non-equilibrium conditions QCD plasma can develop plasma
instabilities, where some modes of the plasma grow exponentially. It has been
argued that these instabilities can play a significant role in the
thermalisation of the plasma in heavy-ion collision experiments. We study the
instability in SU(2) plasmas using the hard thermal loop effective lattice
theory, which is suitable for studying real-time evolution of long wavelength
modes in the plasma. We observe that under suitable conditions the plasma can
indeed develop an instability which can grow to a very large magnitude,
necessary for the rapid thermalisation in heavy-ion collisions.
