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A data-driven active region evolution (DARE) model has been developed tostudy the complex structures and dynamics of solar coronal magnetic fields. Themodel is configured with typical coronal environment of tenuous gas governed bystrong magnetic field, and thus its lower boundary is set at the base of thecorona, but driven by magnetic fields observed in the photosphere. A previousassessment 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 avery strong Lorentz force and therefore spurious flows are generated in theDARE model. Here we further test the DARE by using three sets of data from theFES sliced at incremental heights, which correspond to the photosphere, thechromosphere and the base of the corona. It is found that the key difference inthe three sets of data is the extent of the Lorentz force, which makes thedata-driven model perform very differently. At the two higher levels above thephotosphere, the Lorentz force decreases substantially, and the DARE modelattains results in much better agreement with the FES, confirming that theLorentz force in the boundary data is a key issue affecting the results of theDARE model. However, unlike the FES data, the photospheric field from SDO/HMIobservations has recently been found to be very close to force-free. Therefore,we suggest that it is still reasonable to use the photospheric magnetic fieldas approximation of the field at the coronal base to drive the DARE model.

Testing a Data-driven Active Region Evolution Model with Boundary Data at Different Heights from a Solar Magnetic Flux Emergence Simulation