Astron. Astrophys. 323, 593-598 (1997)

Three-dimensional numerical study of converging flux events

J. Dreher ¹, G.T. Birk ² and T. Neukirch <sup>3

1</sup> Theoretische Physik IV, Ruhr-Universität Bochum, D-44780 Bochum, Germany
² Institut für Astronomie und Astrophysik, Ludwig-Maximilians-Universität München, D-81679 München, Germany
³ School of Mathematical and Computational Sciences, University of St. Andrews, St. Andrews KY16 9SS, Fife, Scotland, UK

Received 30 May 1996 / Accepted 30 July 1996

Abstract

The first self-consistent three-dimensional magnetohydrodynamical simulations of converging magnetic flux events associated with the formation of coronal X-ray bright points are presented. The initial magnetic field results from two magnetic dipoles located below the photosphere at positions and , respectively, and an additional horizontal magnetic field parallel to the line . Both dipole moments are vertical and have equal magnitude but opposite orientation. During the dynamical evolution, a prescribed photospheric convection pattern causes the magnetic dipole-like structures to approach one another. In the early phase of the evolution a current sheet forms in the central region above the polarity inversion line. When the current density exceeds a critical value, anomalous resistivity due to microturbulence is assumed to break the ideal Ohm's law. As a consequence, magnetic reconnection sets in and results in a jet-like plasma flow. The localized plasma heating associated with the reconnection process might account for the flaring of tiny filaments within bright point structures.

Key words: solar corona X-ray bright points solar magnetic fields MHD simulations plasmas

Send offprint requests to: J. Dreher

Contents

• 1. Introduction
• 2. The numerical model
• 3. Simulation results
• 4. Summary and discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: June 5, 1998

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