  The evolution and propagation of coronal mass ejections (CMEs) in
interplanetary space is still not well understood. As a consequence, accurate
arrival time and arrival speed forecasts are an unsolved problem in space
weather research. In this study, we present the ELlipse Evolution model based
on HI observations (ELEvoHI) and introduce a deformable front to this model.
ELEvoHI relies on heliospheric imagers (HI) observations to obtain the
kinematics of a CME. With the newly developed deformable front, the model is
able to react to the ambient solar wind conditions during the entire
propagation and along the whole front of the CME. To get an estimate of the
ambient solar wind conditions, we make use of three different models:
Heliospheric Upwind eXtrapolation model (HUX), Heliospheric Upwind
eXtrapolation with time dependence model (HUXt), and EUropean Heliospheric
FORecasting Information Asset (EUHFORIA). We test the deformable front on a CME
first observed in STEREO-A/HI on February 3, 2010 14:49 UT. For this case
study, the deformable front provides better estimates of the arrival time and
arrival speed than the original version of ELEvoHI using an elliptical front.
The new implementation enables us to study the parameters influencing the
propagation of the CME not only for the apex, but for the entire front. The
evolution of the CME front, especially at the flanks, is highly dependent on
the ambient solar wind model used. An additional advantage of the new
implementation is given by the possibility to provide estimates of the CME
mass.
