Improving predictions of high-latitude coronal mass ejections throughout the heliosphere

Predictions of the impact of coronal mass ejections (CMEs) in the heliosphere mostly rely oncone CME models, whose performances are optimized for locations in the ecliptic plane and at 1 AU (e.g.,at Earth). Progresses in the exploration of the inner heliosphere, however, advocate the need to assess theirperformances at both higher latitudes and smaller heliocentric distances. In this work, we perform 3-Dmagnetohydrodynamics simulations of artificial cone CMEs using the EUropean HeliosphericFORecasting Information Asset (EUHFORIA), investigating the performances of cone models in the caseof CMEs launched at high latitudes. We compare results obtained initializing CMEs using a commonlyapplied approximated (Euclidean) distance relation and using a proper (great circle) distance relation.Results show that initializing high-latitude CMEs using the Euclidean approximation results in ateardrop-shaped CME cross section at the model inner boundary that fails in reproducing the initial shapeof high-latitude cone CMEs as a circular cross section. Modeling errors arising from the use of aninappropriate distance relation at the inner boundary eventually propagate to the heliospheric domain.Errors are most prominent in simulations of high-latitude CMEs and at the location of spacecraft at highlatitudes and/or small distances from the Sun, with locations impacted by the CME flanks being the mosterror sensitive. This work shows that the low-latitude approximations commonly employed in conemodels, if not corrected, may significantly affect CME predictions at various locations compatible with theorbit of space missions such as Parker Solar Probe, Ulysses, and Solar Orbiter.status: publishe