  The rates governing momentum broadening in a quark-gluon plasma with a
momentum anisotropy are calculated to leading-log order for a heavy quark using
kinetic theory. It is shown how the problematic singularity for these rates at
leading-oder is lifted by next-to-leading order gluon self-energy corrections
to give a finite contribution to the leading-log result. The resulting rates
are shown to lead to larger momentum broadening along the beam axis than in the
transverse plane, which is consistent with recent STAR results. This might
indicate that the quark-gluon-plasma at RHIC is not in equilibrium.
