The storing and release of magnetic energy is analogous with what happens when one twist and then cut an elastic. Similarly, magnetic energy is released when magnetic field lines are cut, i.e., when one change their connectivity. This change of connectivity is at the heart of magnetic reconnection. In order that magnetic field lines can be reconnected, narrow layers of intense electric currents must be present. Although reconnection start to be well understood in two dimensions (2D), numerous questions, still unanswered, have been raised these last ten years about the conditions of formation of these current layers and the nature of magnetic reconnection in three dimensions (3D).
Recently, a research group of the Paris Observatory [1] has numerically simulated in 3D, the build-up of these current layers and the following reconnection, using the multi-processors facilities of the Service Informatique de L’Observatoire de Paris. This group has generalized in 3D the necessary conditions for current layers to develop, linking them which general geometries of the magnetic field that do not include any topological singularities, called "hyperbolic flux tubes". This association allows to predict the location of the magnetic reconnection triggering, and eventually to better control it in magnetic confinement laboratory experiments.
References
- [1] Pariat E., Aulanier G. & Démoulin P., New concept for magnetic reconnexion, SF2A, 2006. Aulanier , Pariat, Démoulin & DeVore, Slip-running reconnexion in quasi-separatrix layers, 2006, Solar Physics, à paraître. Aulanier, Pariat & Démoulin, Current sheet formation in quasi-separatrix layers and hyperbolic flux tubes, 2005, Astronomy & Astrophysics, 444, 961-976.