On the combination of ACE data with numerical simulations to determine the initial characteristics of a CME

Abstract

Aims. Our goal is to combine the Advanced Composition Explorer (ACE) data with numerical simulations to determine the initial characteristics of the halo coronal mass ejection (CME), which was observed on April 4, 2000.Methods. The evolution of a CME from the Sun to 1 AU is simulated in the framework of 2.5 D (axi-symmetric) ideal Magnetohydrodynamics (MHD). The initial parameters of the CME model are adjusted to reproduce the ACE data as accurately as possible. The initial parameters leading to the best fit are then assumed to be the most plausible initial parameters of the CME event.Results. Once the ACE data and the transit time were successfully reproduced, we concluded that, at 1.5 R⊙, the CME had a maximal magnetic field strength of 2.5 × 10-4 T and a total mass of 6.7 × 1012 kg, and the CME linear speed up to 30 R⊙ was 1524 kms-1. © 2008 ESO.