Fredagskollokvium: : Occurrences of fast and possibly cannibalistic solar coronal mass ejections: insights from flux rope simulations

We present results from magneto-hydrodynamic simulations of the
development of homologous sequence of coronal mass ejections (CMEs)
and demonstrate their so-called cannibalistic behavior. These CMEs
originate from the repeated formations and partial eruptions of kink
unstable flux ropes as a result of continued emergence of a twisted
flux rope across the lower boundary into a pre-existing coronal
potential arcade field. Our simulation shows that a CME erupting into
the open magnetic field created by a preceding CME has a higher speed.
The second of the three successive CMEs in one of the simulations is
cannibalistic, catching up and merging with the first into a single
fast CME before exiting the domain. All the CMEs including the leading
merged CME, attained speeds of about 1000 km s-1 as they exit the
domain. The reformation of a twisted flux rope after each CME eruption
during the sustained flux emergence can naturally explain the X-ray
observations of repeated reformations of sigmoids and
"sigmoid-under-cusp" configurations at a low-coronal source of
homologous CMEs.