  The physical processes taking place at the edge region are crucial for the
operation of tokamaks as they govern the interaction of hot plasma with the
vessel walls. Numerical modeling of the edge with state-of-the-art codes
attempts to elucidate interactions between neoclassical drifts, turbulence,
poloidal and parallel flows that control the physical set-up of the SOL region.
Here, we present post-processing analysis of simulations from the gyrokinetic
code XGC1, comparing edge turbulence characteristics from a simulation of
DIII-D against one of C-Mod. We find that the equilibrium $E \times B$ flux
across the separatrix has a similar poloidal pattern in both discharges which
can be explained by magnetic drifts and trapped ion excursions. However,
collisionality is noted to play a major role in that it prevents local charge
accumulations from having global effects in C-Mod. In both cases, turbulent
electron heat flux is higher than the ion one. This seems to be a universal
characteristic of the tokamak edge. We identify turbulent frequencies and
growth rates of the dominant mode in both simulations. In C-Mod, these numbers
point to the presence of a drift wave. In DIII-D, linear simulations with Gene
reveal a trapped electron mode. Furthermore, we present the amplitude and size
distributions of the blobs from both simulations. Amplitude distributions are
in qualitative agreement with experimental observations while size
distributions are consistent with the fact that most blobs are not connecting
to the divertor plates and suggest that they are generated by the shearing of
the turbulent modes.
