Sketch of the initial configuration: the opaque horizontal torus is a gaseous disc with the distance from the centre of the tube to the centre of the torus R_D = 1 kpc and the radius of the tube r_D = 0.2 kpc; the translucent vertical ring is a magnetic loop with the same radius and thickness as that of the gaseous disc. The central sphere of radius r_s = 0.2 kpc represents a central region with high pressure and velocity: the ejection region.