Solar plasma structuring due to two-dimensional pinch effect over the photosphere

Abstract

We study the behavior of the solar plasma over the photosphere in the zone of contact of oppositely directed magnetic fields. A special technique of numerical simulation is used, which allows passing to the class of generalized functions as soon as the solution loses smoothness. An initial-value problem is solved for the self-consistent nonlinear system of equations of collisional magneto-gas-dynamics under the assumption that the distribution of physical quantities is two-dimensional and the plasma has an initial temperature of 50 000 degrees. It is assumed that the magnetic field lines are straight, the physical quantities are constant along them, and the resulting fluid velocity is perpendicular to the magnetic field. It is shown that a pinch effect develops under such conditions, which gives rise to much more diverse effects in a natural ambient medium than in a laboratory plasma. The pinch effect produces narrow, variously directed jets of matter (including those going beyond the zone of contact of the fields), forms cross-shaped patterns in the distribution of the magnetic field, velocity and density, and gives rise to specific temperature nonuniformities. In the center of the contact zone, the plasma temperature increases (we terminate the computations when it doubles). The jet velocity can exceed 20 km/s.