Project description – The Structure and Evolution of Solar Magnetic Flux Ropes and Their Magnetosheaths (SolMAG)

Coronal Mass Ejections (CMEs) are gigantic eruptions that carry huge amounts of plasma and magnetic flux from the Sun’s atmosphere in interplanetary space. The interests in their origin, structure, and dynamics reach from fundamental plasma physics to paramount impact on the Sun and surrounding planets. One of the most outstanding problems in the studies of CMEs is the lack of reliable information on their magnetic field properties until observed directly. This severely limits our understanding of initiation and evolution of CMEs and their consequences in the heliosphere. In particular, the realistic knowledge of the magnetic field in CMEs is one of the critical missing pieces in improving long-lead-time space weather forecasts.

SolMAG projects aims at getting realistic magnetic fields in coronal mass ejections (CMEs) from Sun to Earth. CMEs consist of two key parts; the driving ejecta and a turbulent sheath region. The three Work Packages in SolMAG are:

WPA Quantification of Magnetic Structure and Evolution of CME Flux Ropes analyses CME flux ropes from the point of their formation at the Sun until sampled in-situ. The focus of this WP is on the intrinsic magnetic structure of CMEs at the time of the eruption and its early evolution in the low corona (few first solar radii). The key tools are the time-dependent magnetofrictional method and multi-wavelength analysis.

WPB: Comprehensive Characterization of CME Sheaths Regions studies CME sheaths using an extensive multi-scale in-situ analysis and simulations. Turbulent CME sheaths are currently poorly understood, even on a macroscopic scale. Sheaths accrete gradually as CMEs plough supersonically through the interplanetary space and complex physical processes at the shock and at the flux rope leading edge lead to highly irregular variations. This WP focuses in particular on quantifying the occurrence of various plasma waves in CME sheaths and nature of magnetic field fluctuations.

WPC Sheath and CME Interactions studies one of the most complex processes related to CMEs; the merging of multiple eruptions using data-driven simulations. This WP also investigates the interaction of CME sheaths with the Earth’s MagnetoSheaths, i.e., the interaction between two turbulent sheath structures.