Fig. 5

Structure of the 3D plasmoid in event-5. Contour maps of (\(B_{y}\), \(\eta J\), \(U_{z}\)) are similar to those of a local area of Fig. 4. Black arrows are the plasma flow vector field (\(U_{x}\), \(U_{z}\)). The x-directional arrow’s maximum length on these figures has reached the Alfven speed measured in the upstream magnetic field region (\(y>1.0\)). The scale of the z-directional arrow’s length is emphasized by three times of the x-directional arrow’s length. a B _y , b ηJ, c U _z