Modeling the 1994 April 14 polar crown SXR arcade using three-dimensional magnetohydrostatic equilibrium solutions

The coronal magnetic held in the polar crown soft X-ray (SXR) arcade of 199 4 April 14 has been computed using the global photospheric magnetic field d istribution constructed for the time of interest and the three-dimensional magnetohydrostatic equilibrium solutions. In the solutions there are two fr ee parameters, a and a, respectively, characterizing the effect of the held -aligned and horizontal electric currents. Magnetic held configurations hav e been determined for various combinations of a and a. The magnetic arcade computed with alpha-->0 and a = 0.9 agrees best in shape and size with the well-developed polar crown SXR arcade. This suggests that the well-develope d SXR arcade has a potential-like magnetic configuration with non-held-alig ned currents. The computed loci of the apexes of lines of force that close above 1.3 R. match the shape of the bright axial features superposed on the well-developed SXR arcade. This suggests that newly opened lines of force may have reconnected only above 1.3 Ro, and consequently the pre-eruption c losed lines of force may not be completely opened up during the eruption ph ase. The SXT images before the formation of the SXR loop show the occurrenc e of dimmings, supporting the inference of partially "transient" coronal op ening.