What is a magnetic flux tube?
Seminar Room 1, Newton Institute
Using 3D nonlinear MHD simulations, we examine the interaction of localised velocity shear and magnetic fields. We find that buoyant magnetic structures resembling flux tubes are generated by the interaction of induced magnetic buoyancy and the shear. Depending on the parameters, the generation process can result in steady (equilibrated) structures, or cyclic and chaotic emerging structures. By integrating along magnetic field lines and constructing return maps, we examine the relationship of these spontaneously-produced structures to the preconceived concept of a flux tube. We discuss how these results impact our simple ideas of a flux tube as an object with an inside and an outside whose dynamics are constrained by this assertion.