Snapshot of the cuts in the xz plane at the center of the curtain obtained with the 3D MHD model at t = 14.7τ_A, showing the propagating fast magnetosonic disturbance produced by the boundary pulse that models the effects of the flare. a) Perturbed density Δρ/ρ(t = 0). Field lines associated with the active region curtain are shown. The distortion of the field lines by the propagating fast magnetosonic disturbance is evident. b) Velocity magnitude and the direction (arrows are shown for | v | greater than 6% of the absolute maximal velocity). c) Current density map j². d) Magnitude of the magnetic field and the direction. The results show the effects of the initial induced wave pulse and the response of the curtain.