On the re-connexion of magnetic lines of force

Abstract

The magnetic field and flow with an X-type neutral point or stagnation point are studied numerically for the steady state of incompressible, finitely conducting, viscous fluid in two dimensions. There appear two transition layers connecting smoothly the regions on either side, each of which contains almost uniform magnetic field and flow. The electric currents are concentrated in the vicinity of the neutral point and along the transition layers. The magnetic field is regarded as almost frozen in the fluid in other current-free regions, even in the case of moderate conductivities. The current-core over the neutral point is accompanied by a remarkable shear of currents, which may contribute to reducing the local electrical conductivity effectively. Thus the re-connexion of magnetic lines of force may be possible even in very highly conducting fluids. It is shown that the re-connexion is not essentially influenced by dissipations due to finite electrical conductivity or viscosity, but definitely by external conditions such as the applied electric field in the magnetic field and flow.