Abstract


  3D MHD SIMULATIONS OF THE EJECTION OF A MAGNETIC FLUX ROPE

  P. Pagano, University of St Andrews, pp25@st-andrews.ac.uk
  D. Mackay, University of St Andrews, dhm@st-andrews.ac.uk

CMEs are the main driver of Space Weather. According to the flux rope ejection model, a magnetic flux rope is ejected from the solar corona and reaches the interplanetary space where it interacts with the pre-existing magnetic fields and plasma. Both gravity and the stratification of the corona affect the early evolution of the flux rope which is crucial for the effectiveness of the event.
We study the life span of a flux rope and the role of gravitational stratification on the propagation of CMEs and how it influences the speed and shape of CMEs and under what conditions the flux rope ejection becomes a CME or when it is quenched. We run a set of MHD simulations that adopt an eruptive initial magnetic configuration varying the temperature of the backgroud corona and the intensity of the initial magnetic field and subsequently we use an automatic technique to track the expansion and the propagation of the magnetic flux rope in the MHD simulations. Our study shows that gravitational stratification plays a significant role in determining whether the flux rope ejection will turn into a full CME or whether the magnetic flux rope will stop in the corona.
These simulations are run by coupling the GNLFFF model of Mackay and van Ballegooijen with the MHD code AMRVAC. This technique allows to model the full life span of flux rope: from generation to ejection. We will also discuss of the potentiality of this technique to empower our Space Weather prediction capability.