Connecting 3D Evolution of Coronal Mass Ejections to Their Source Regions

Abstract

Since coronal mass ejections (CMEs) are the major drivers of space weather, it is crucial to study their evolution starting from the inner corona. In this work we use graduated cylindrical shell model to study the 3D evolution of 59 CMEs in the inner (<3 R ⊙) and outer (>3 R ⊙) corona using observations from COR-1 and COR-2 on board the Solar TErrestrial RElations Observatory (STEREO) spacecraft. We identify the source regions of these CMEs and classify them as CMEs associated with active regions (ARs), active prominences (APs), and prominence eruptions. We find 27% of CMEs show true expansion and 31% show true deflections as they propagate outwards. Using 3D kinematic profiles of CMEs, we connect the evolution of true acceleration with the evolution of true width in the inner and outer corona, thereby providing observational evidence for the influence of the Lorentz force on the kinematics to lie in the height range 2.5–3 R ⊙. We find a broad range in the distribution of peak 3D speeds and accelerations, ranging from 396 to 2465 km s−1 and 176 to 10,922 m s−2 respectively, with a long tail toward high values coming mainly from CMEs originating from ARs or APs. Further, we find that the magnitude of true acceleration is inversely correlated with its duration with a power-law index of −1.19. We believe that these results will provide important inputs for the planning of upcoming space missions that will observe the inner corona and for models that study CME initiation and propagation.