资源环境科技发展态势分析平台

We develop an optimization approach to model the magnetic field configuration of magnetic clouds, based on a linear‐force free formulation in three dimensions. Such a solution, dubbed the Freidberg solution, is kin to the axi‐symmetric Lundquist solution, but with more general “helical symmetry”. The merit of our approach is demonstrated via its application to two case studies of in‐situ measured magnetic clouds. Both yield results of reduced χ² ≈ 1. Case 1 shows a winding flux rope configuration with one major polarity. Case 2 exhibits a double‐helix configuration with two flux bundles winding around each other and rooted on regions of mixed polarities. This study demonstrates the three‐dimensional (3D) complexity of the magnetic cloud structures.