Separator current sheets: Generic features in minimum-energy magnetic fields subject to flux constraints

摘要: Equations are found for force-free magnetic equilibria in the “coronal half-space” z>0, subject to boundary conditions on normal field at z=0. The distribution of is assumed be composed NS isolated unipolar source regions arbitrary shape, arranged arbitrarily plane. by minimizing energy constraints total flux interconnecting pairs regions. For interconnected ND ways, there Nc=ND−NS+1 distinct field. Minimization these leads an Nc-dimensional space equilibria, given data. All field-lines connecting current-free, but equilibrium contains Nc current-sheets lying certain interfaces. In a two-dimensional current sheets occur points topologically equivalent X-type neutral potential three-dimensional topologically...