Inverse and normal coronal mass ejections: evolution up to 1 AU

Abstract

Simulations of Coronal Mass Ejections (CMEs) evolving in the interplanetary (IP) space from the Sun up to 1 AU are performed in the framework of ideal magnetohydrodynamics (MHD) by the means of a finite volume, explicit solver. The aim is to quantify the effect of the initiation parameters, such as the initial magnetic polarity, on the evolution and on the geo-effectiveness of CMEs. The CMEs are simulated by means of a very simple model: a high density and high pressure magnetized plasma blob is superposed on a background steady state solar wind model with an initial velocity and launch direction. The simulations show that the initial magnetic polarity substantially affects the IP evolution of the CMEs influencing the propagation velocity, the shape, the trajectory and even the geo-effectiveness. We also tried to reproduce the physical values (density, velocity, and magnetic field) observed by the ACE spacecraft after the halo CME event that occurred on April 4, 2000.