Spin instabilities in an ultra-cold gas

We study spin dynamics and instabilities in an out-of-equilibrium quantum gas. Using an optical technique, we imprint arbitrary one-dimensional spin structures in a trapped gas of $^{87}$Rb atoms near quantum degeneracy. These spin structures can exhibit instabilities, such as the Castaing instability, in which a strong longitudinal spin gradient is unstable to transverse perturbations. This instability can lead to large-amplitude spontaneous transverse magnetization oscillations. We report on progress towards driving and observing these instabilities.