Magnetic ambient field lines of the 2021 March 21 event. The left panel shows the topology of the field lines (the white and gray lines correspond to closed field lines, while the blue lines correspond to negative open lines) and the topological path (the orange dashed line). The gray lines correspond to the arcade overlying the source region. The colored dots show the triangulated trajectory and the black line shows the eruptive path of the event, as in Figure 2. The right panel shows the isocontours for the magnitude of the magnetic field, the yellowish ones being stronger and decaying toward the purple contours. The white dashed line indicates the gradient path. An interactive view of this figure, with the information from both panels displayed together on a 3D visualization, is available. The interactive view allows users to hover above, zoom in on, and rotate the figure to explore it in a more comprehensive way.

An interactive version of this figure is available in the online article.

An interactive version of this figure is available.

An interactive version of this figure is available in the online journal.