  Coronal Mass Ejections (CMEs) are the primary source of strong space weather
disturbances at Earth. Their geoeffectiveness is largely determined by their
dynamic pressure and internal magnetic fields, for which reliable predictions
at Earth are not possible with traditional cone CME models. We study two
Earth-directed CMEs using the EUropean Heliospheric FORecasting Information
Asset (EUHFORIA) model, testing the predictive capabilities of a linear
force-free spheromak CME model initialised using parameters derived from
remote-sensing observations. Using observation-based CME input parameters, we
perform MHD simulations of the events with the cone and spheromak CME models.
Results show that spheromak CMEs propagate faster than cone CMEs when
initialised with the same kinematic parameters. We interpret these differences
as due to different Lorentz forces acting within cone and spheromak CMEs,
leading to different CME expansions. Such discrepancies can be mitigated by
initialising spheromak CMEs with a reduced speed corresponding to the radial
speed only. Results at Earth evidence that the spheromak model improves the
predictions of B(Bz) up to 12-60(22-40) percentage points compared to a cone
model. Considering virtual spacecraft located around Earth, B(Bz) predictions
reach 45-70%(58-78%) of the observed peak values. The spheromak model predicts
inaccurate magnetic field parameters at Earth for CMEs propagating away from
the Sun-Earth line, while it successfully predicts the CME properties and
arrival time in the case of strictly Earth-directed events. Modelling CMEs
propagating away from the Sun-Earth line requires extra care due to limitations
related to the assumed spherical shape. The spatial variability of modelling
results and the typical uncertainties in the reconstructed CME direction
advocate the need to consider predictions at Earth and at virtual spacecraft
around it.
