This template restarts from a PotentialField or MagnetofrictionalRelaxation snapshot and linearly interpolates the three-component magnetic sequence at the lower boundary. It never reads V_XXXX.dat; velocity treatment belongs to the AMRVAC user boundary implementation. The current B-only implementation extrapolates the plasma velocity from the interior, fixes the boundary density and pressure to their initial atmosphere, and imposes the time-interpolated B in the innermost ghost layer. driving_time_scale defaults to 12. Only the two frames bracketing the current observation time are kept in memory.

bottom_numberdensity_cm3 optionally renormalizes the complete initial atmosphere so that its number density at the physical lower boundary has the requested value. This preserves the atmosphere temperature profile and keeps the initial interior and fixed ghost-cell boundary continuous. A value of -1 uses the atmosphere model's original normalization.

The four base parameter sets under par_zero_beta, par_isothermal, par_adiabatic, and par_thermodynamic mirror the DataConstrained models. The Python workflow selects one and writes data_driven.par, including the portable boundary-series path and driving_time_scale.

For direct B driving, a coronal atmosphere is recommended. Chromospheric and transition-region stratification remains available, but its steep density and temperature gradients can make the driven lower boundary substantially less stable; both staging and AMRVAC startup emit a warning when it is selected.