  Using fully kinetic 3D simulations, the reconnection dynamics of asymmetric
current sheets are examined at the Earth's magnetopause. The plasma parameters
are selected to model MMS magnetopause diffusion region crossings with guide
fields of 0.1, 0.4, and 1 of the reconnecting magnetosheath field. In each
case, strong drift-wave fluctuations are observed in the lower-hybrid frequency
range at the steep density gradient across the magnetospheric separatrix. These
fluctuations give rise to cross-field electron particle transport. In addition,
this turbulent mixing leads to significantly enhanced electron parallel heating
in comparison to 2D simulations. We study three different methods of
quantifying the anomalous dissipation produced by the drift fluctuations, based
on spatial averaging, temporal averaging, and temporal averaging followed by
integrating along magnetic field lines. Comparison of the different methods
reveals complications in identifying and measuring the anomalous dissipation.
Nevertheless, the anomalous dissipation from short wavelength drift
fluctuations appears weak for each case, and the reconnection rates observed in
3D are nearly the same as in 2D models. The 3D simulations feature a number of
interesting new features that are consistent with recent MMS observations,
including cold beams of magnetosheath electrons that penetrate into the hotter
magnetospheric inflow, the related observation of decreasing temperature in
regions of increasing total density, and an effective turbulent diffusion
coefficient that agrees with predictions from quasi-linear theory.
