Neutron stars can have strong magnetic fields. After the merger, magnetic fields can be amplified by different mechanisms. Magnetic fields are likely important for the creation of Short Gamma Ray Bursts.
The video shows the emergence of an ordered magnetic field structure after the merger. Regions of strong magnetic field are shown as transparent colors. The initial neutron stars are shown in white. The merger first produces a massive neutron star (shown in white) which collapses to a black hole (shown in yellow).
The structure of the emerging magnetic field is shown in the image. The thin tubes represent strong field lines. One can see a toroidal field in the disk, caused by the shear in the rotating disk matter. The debris disk is shown as bluish surface (cut in half to allow looking inside). There is a second structure resembling a tornado at the edge of a cone shaped region of low mass density. The latter is shown as yellow surface (also cut open).