Same as Figure 5 but from a top-down perspective, showing GT (left), Δt = 20δt Data-Driven (middle) and Δt = 100δt Data-Driven (right) simulations at four times throughout the spheromak expansion (top to bottom at Courant steps 0, 125, 250, and 375). The vertical magnetic field is shown in gray scale in the z = 1.14 plane. Seed points of the field lines are initiated at the z = 1.25 plane (see text in Appendix F following Equation (F12)). The animation shows the expansion of the field lines through the driving layer. The vertical magnetic field in the driving layer starts at zero. Subsequently, the bipolar magnetic field appears as an expanding yin-yang pattern that rotates as the spheromak enters the driven volume. Both the field lines and the vertical magnetic field in the driving layer match very well between the GT and higher-cadence Δt = 20δt Data-Driven simulations, but the lower-cadence simulation, with Δt = 100δt, is severely distorted. The animation runs from time zero to 1.46561 with a real-time duration of 3 s.

(An animation of this figure is available.)

The video/animation of this figure is available in the online journal.