Movie S2.

Simulation of two scenarios of the annihilation event of the ±1/2 defect. (Upper) Defect line perpendicular to the nematic far field. (Lower) Defect line parallel to the nematic far field. Short black lines represent the director field, and blue curves are streamlines. In the zoom-in frames, red arrows are the velocity vectors. In the parallel case, defects take a longer time to annihilate. (Time unit, tau = 0.8 s.)