A model to understand the flux rope distortions resulting of the propagation

The distorted-cylindrical analytical flux-rope model constitutes the higher level of complexity above that of the first approach on distortion established by the elliptical-cylindrical geometry. The framework of this series of models was established by Nieves-Chinchilla et al. 2016 (CC model) with the circular-cylindrical analytical flux rope model. The model describes the magnetic flux rope topology with distorted cross-section as a possible consequence of the flux-rope interaction with the solar wind. Following the mathematical formulation on Nieves-Chinchilla et al 2018 (ApJ) (EC model), the model is fully described in non-orthogonal coordinate system for a general cross-section distortion. As previous CC and EC models, this model is generalized in terms of the radial dependence of the poloidal and axial current density component.

The reconstruction technique has been adapted to the new geometry and applied to several simulated spacecraft trajectories along a distorted flux-rope to study the effects and changes in the magnetic field configuration. In addition, the misalignment between current density and magnetic field is studied in detail for the individual cases of a specific internal current density distribution of the axial and poloidal current density components.