  We introduce the phenomenology of elliptic flow in nuclear collisions, and
argue that its scaling across energies, rapidities and system sizes could be
suggestive of a QCD-based rather than a hydrodynamical explanation. As a
hypothesis for such an explanation, we show that the GLR equation develops
unstable modes when the parton distribution function is generalized to depend
on azimuthal angle. This generally means the structure function aquires an
azimuthal dependence. We argue that this process is a plausible alternative
explanation for the origin of elliptic flow, one that naturally respects the
scaling experimentally observed.

Nuclear Theory;High Energy Physics - Phenomenology