Eruption and propagation of twisted flux ropes from the base of the solar corona to 1 au

Abstract

Context. Interplanetary coronal mass ejections (ICMEs) originate from the eruption of complex magnetic structures occurring in our star’s atmosphere. Determining the general properties of ICMEs and the physical processes at the heart of their interactions with the solar wind is a hard task, in particular using only unidimensional in situ profiles. Thus, these phenomena are still not well understood. Aims. In this study we simulate the propagation of a set of flux ropes in order to understand some of the physical processes occurring during the propagation of an ICME, such as their growth or their rotation. Methods. We present simulations of the propagation of a set of flux ropes in a simplified solar wind. We consider different magnetic field strengths and sizes at the initiation of the eruption, and characterize their influence on the properties of the flux ropes during their propagation. We use the 3D magnetohydrodynamics (MHD) module of the PLUTO code on an adaptive mesh refinement grid. Results. The evolution of the magnetic field of the flux rope during the propagation matches evolution law deduced from in situ observations. We also simulate in situ profiles that spacecraft would have measured at the Earth, and we compare these data with the results of statistical studies. We find a good match between simulated in situ profiles and typical profiles obtained in these studies. During their propagation, flux ropes interact with the magnetic field of the wind, but still show realistic signatures of ICMEs when analyzed with synthetic satellite crossings. We also show that flux ropes with different shapes and orientations can lead to similar unidimensional crossings. This warrants some care when extracting the magnetic topology of ICMEs using unidimensional crossings.