  The inclusion of drifts in plasma edge codes like SOLPS-ITER is required to
match simulation data with experimental profiles. However, this remains
numerically challenging. In this paper, the effect of some numerical factors on
the final plasma solution is investigated. This study is performed on three
EAST simulations in upper single null configuration: an attached purely
deuterium case, an attached case with limited Ne-seeding and a detached
Ne-seeded case. The effects of the anomalous conductivity and anomalous
thermo-electric coefficient on the plasma potential are investigated. Next, the
effect of the employed grids is shown. In order to investigate these effects,
accurate drift simulations are needed. Therefore, the employed time step and
used numerical parameters are discussed for the three studied simulations. For
all presented simulations, it is verified that the restriction of the grid to
the first flux surface tangent to the main chamber wall has only a small effect
on the divertor solution. This means that the main power dissipation takes
place inside the simulated domain and only a small fraction of the power is
leaving the B2.5 grid trough the grid boundary closest to the first wall.
Finally the effect of drifts on the asymmetry between the inner and outer
target for EAST simulations is demonstrated.
