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Context
Two-dimensional magnetic X-points are locations where the magnetic field vanishes locally. They are key scenarios for energy conversion via magnetic reconnection, and the detailed study of the dynamics arround them, such as current sheet formation, is crucial for understanding these phenomena.

What are you watching
This movie shows the first part of the dynamical evolution of a 2D magnetic X-Point towards a Magnetohydrostatic equilibrium. In the left, magnetic field lines (white lines) over a contour plot of electric current density (J, whose only non-zero component is directed in the z-direction). In the top right, surface of electric current density. In the bottom right, horizontal and vertical cuts through the middle of the box of current density (zoomed in).

Initial setup and relaxation
The initial state has a non-zero magnetic force (it is not in equilibrium), and no velocity flow. The initial magnetic force provides the plasma with kinetic energy (velocity), which is damped out by viscous forces, and partly converted into heat (internal energy of the plasma) via viscous heating, so that the total energy is conserved. The relaxation is ideal, i.e. non-resistive. This means that magnetic reconnection is not allowed: There is no ohmic dissipation, the field is frozen into the fluid, the field connectivity cannot change.

Main features
Current density accumulates at the location of the magnetic null and also along the four separatrices of the system. The first part of the evolution consists of a quick MHD relaxation after which the field is in equilibrium everywhere save at the null point. The second part shows a very slow increase of the current at the location of the null, which is found to match with a positive power of time.

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