PI: Peter Wyper

Coronal mass ejections (CMEs) from the Sun are massive expulsions of plasma and magnetic field originating in the Sun’s atmosphere (the solar corona). They are the main driver of Space Weather around the Earth, and come in a variety of different morphologies. In a new study involving simulation data developed with Dirac resources we have employed a new forward modelling code to produce synthetic remote-sensing and in-situ observations of a simulated CME as it would be observed by satellites currently orbiting the Sun. A key feature of this simulation was its high resolution, resolving small-scale structures within the CME that have not been captured by previous studies. Our forward modelling showed the associated observational signatures of this sub-structure for the first time. This study was particularly timely, coming at a time when the Parker Solar Probe (PSP) and Solar Orbiter missions are observing more fine-scale structure within the solar wind and CMEs than ever before.

An example of this forward modelling is shown in the figure. On the right of panel (a) a CME observed by the WISPR instrument onboard PSP is shown. The “core” of the CME is highlighted with dashed lines, while the arrows point to post-CME outflows and sub-structure. This CME was observed by PSP from the side as it heads close to Earth (left of the panel). For comparison, panel (b) shows a similar view of the forward modelled white light in our simulation, where we captured for the first time similar post-CME outflow sub-structures (arrows). We also explored synthetic EUV and in-situ measurements and discuss their interpretation in relation to current satellite observations and capabilities.

This work was published in the Astrophysical Journal: Lynch et al. 2025, DOI: 10.3847/1538-4365/adb14e.