  A data-driven active region evolution (DARE) model has been developed to
study the complex structures and dynamics of solar coronal magnetic fields. The
model is configured with typical coronal environment of tenuous gas governed by
strong magnetic field, and thus its lower boundary is set at the base of the
corona, but driven by magnetic fields observed in the photosphere. A previous
assessment of the model using data from a flux emergence simulation (FES)
showed that the DARE failed to reproduce the coronal magnetic field in the FES,
which is attributed to the fact that the photospheric data in the FES has a
very strong Lorentz force and therefore spurious flows are generated in the
DARE model. Here we further test the DARE by using three sets of data from the
FES sliced at incremental heights, which correspond to the photosphere, the
chromosphere and the base of the corona. It is found that the key difference in
the three sets of data is the extent of the Lorentz force, which makes the
data-driven model perform very differently. At the two higher levels above the
photosphere, the Lorentz force decreases substantially, and the DARE model
attains results in much better agreement with the FES, confirming that the
Lorentz force in the boundary data is a key issue affecting the results of the
DARE model. However, unlike the FES data, the photospheric field from SDO/HMI
observations has recently been found to be very close to force-free. Therefore,
we suggest that it is still reasonable to use the photospheric magnetic field
as approximation of the field at the coronal base to drive the DARE model.
