Magnetopause transects

A novel method is described for reconstruction of two‐dimensional current‐layer structures from measurements taken by a single spacecraft traversing the layer. In its present form, the method is applicable only to 2D magneto‐hydrostatic structures that are passively convected past the observing spacecraft. It is tested on a magnetopause crossing of the tangential‐discontinuity type by the spacecraft AMPTE/IRM. The magnetic structures recovered include a magnetic island located between two X‐type nulls as well as a magnetic ‘worm hole’ through which a bundle of weak magnetic flux appears to connect the magnetosphere and the magnetosheath.