HeXCor: A Hybrid Magnetic Flux-rope Model of Coronal Mass Ejections Combining In Situ Measurements with Remote Sensing Observations

Abstract This paper presents Heliospheric conneXions for Coronal mass ejections (HeXCor), a new coronal mass ejection (CME) flux rope (FR) reconstruction model that combines the geometry of the graduated cylindrical shell (GCS) model, defined from remote sensing imagery, with a modified cylindrical magnetic field solution inferred from in situ data. The usage of synergistic remote sensing and in situ data allows HeXCor to reconstruct an advanced magnetic FR model of CMEs with both global 3D geometry and internal magnetic field defined. The model is validated with four case studies of Earth-affecting CMEs from 2010 to 2014 observed in the corona by Solar and Heliospheric Observatory and Solar TErrestrial RElations Observatory’s spacecraft with large separation angles. It is shown that the in situ fitting capability is comparable to traditional cylindrical fittings while uniquely providing global structural context. The model also uniquely defines both the poloidal and toroidal impact parameters to fully describe the characteristics of CME impacts. Two of the events (2012 July 12 and 2011 March 25 CMEs) are found to follow the basic assumptions of radial and self-similar expansion from the Sun to Earth, while the other two (2010 May 23 and 2013 April 11 CMEs) likely experience deflection in the propagation direction and change in axial orientation. These results demonstrate how HeXCor provides a realistic and informative CME model that is comprised of accurate 3D global geometry with internal magnetic fields.