Magnetic field lines superposed by the contour map of the two-dimensional distribution of the radial velocity field from 1 to 8  R _☉. The field lines are represented by the contours of the magnetic flux function with the contour level separated by ψ = 0.05ψ ₀. Panel ( a) is for the initial quadrupolar field and solar wind velocity, panels ( b)–( d) depict the calculated conditions at various instants. The separatrix associated with the original quadrupolar field (ψ = 0.3697ψ ₀) is shown in red curves. The three lines in green, red, and yellow color in the blob region are given by ψ = 0.655, 0.66, and 0.665ψ ₀, referred to as line A, B, and C in the text. To show features in the contour map of the radial velocity, the magnetic field lines are omitted in one of the hemispheres in ( b)–( d). The long-term dynamical evolution (in two days from t = 0 to 48 hr) of the triple-streamer solar wind blob system is shown in an in the electronic edition of the Astrophysical Journal.