Unstable dynamics of Yang-Mills fields at early times of heavy ion collisions

The quark gluon plasma as produced in heavy ion collisions is exposed to early anisotropies in momentum space due to its rapid expansion. Such anisotropies can lead to non-abelian plasma instabilities, driven by unstable gluonic modes that grow exponentially fast. These plasma instabilities can be simulated using a discretized version of gauge-covariant Boltzmann-Vlasov and Yang-Mills equations. In the non-expanding case, a turbulence cascade forms, which is associated with an approximately linear growth of energy in collective fields. Early longitudinal expansion slows down the growth of unstable modes, and the formation of soft gluonic fields depends crucially on the initial conditions assumed.