Dynamics of CMEs in the LASCO Field of View - Statistical Analysis

Abstract

A large set of CMEs (2207) has been selected to study their dynamics in the SOHO/LASCO field of view (LFOV). These selected events have at least seven height-time measurements and their acceleration can be determined separately in the C2 and C3 LFOVs. It was demonstrated that the balance between the aerodynamic drag and driving Lorentz forces may change during CME propagation in the LFOV. The drag force dominates the CME propagation close to the Sun (in the C2 LFOV), but farther from the Sun (in the C3 LFOV) the Lorentz force takes over the drag force. We also demonstrated that the acceleration of CMEs depends not only on their velocities but also on their masses and widths. Less massive CMEs (mass <3×10¹⁴ kg) are generally decelerated and more massive CMEs (mass >3×10¹⁴ kg) are accelerated in the LFOV. Based on the acceleration behavior we are able to classify the observed events into four different types.