Density contour, magnetic streamlines, and flow streamlines for an expanding galactic bubble with a large-scale magnetic field with a thick galactic disk at the left (B = 10⁻⁴ Gauss) and the right (B = 10⁻² Gauss) at t = 10 Myr. Left: density contour showing variations in density and the magnetic streamlines representing the direction and strength of the magnetic field, color-coded to indicate their emergence zone. Right: flow streamlines indicating the motion of matter, also color-coded to indicate their emergence zone.