Abstract Details

Name: Nishtha Sachdeva
Affiliation: Indian Institute of Science Education and Research, Pune
Conference ID: ASI2017_416
Title : CME Propagation Dynamics: Relative importance of Lorentz forces and solar wind drag
Authors and Co-Authors : Nishtha Sachdeva & Prasad Subramanian
Abstract Type : Poster
Abstract Category : Sun and the Solar System
Abstract : With the availability of extensive data from STEREO & LASCO observations we use Graduated Cylindrical Shell model to reconstruct 3D geometrical structure of a set of 38 Coronal Mass Ejections (CMEs). We attempt to quantify the relative contributions of the driving Lorentz forces and the solar wind aerodynamic drag acting on CMEs. In doing so we appeal to Torus Instability model and drag based model. We find that the Drag-based models typically succeed only if they are initiated at heliocentric distances as large as 15-50 Rs and that the Lorentz forces generally peak between 1.65 and 2.35 Rs for all CMEs. For fast CMEs, Lorentz forces become negligible in comparison to aerodynamic drag as early as 3-4 Rs. For slow CMEs, however, they become negligible only by 12-50 Rs. We also quantify the fall in peak Lorentz forces as the solar wind drag takes over. This work provides a framework for describing the Lorentz forces using Torus Instability model based on the drag force analysis. Combining the effects of these two forces, our results are expected to be important in building a comprehensive physical model for understanding the Sun-Earth dynamics of CMEs.