Evolution of interplanetary coronal mass ejection complexity: a numerical study through a swarm of simulated spacecraft

TL;DR

This study uses numerical simulations with a swarm of spacecraft to analyze how interplanetary coronal mass ejections (CMEs) evolve in magnetic complexity during propagation, especially when interacting with solar wind structures.

Contribution

It introduces a novel approach of using a swarm of simulated spacecraft to quantify CME complexity evolution during propagation, considering interactions with solar wind features.

Findings

Interaction with solar wind streams doubles the likelihood of increased CME complexity.

Numerical simulations effectively model CME evolution and interactions in interplanetary space.

Results support multi-point CME observation strategies for future space missions.

Abstract

In-situ measurements carried out by spacecraft in radial alignment are critical to advance our knowledge on the evolutionary behavior of coronal mass ejections (CMEs) and their magnetic structures during propagation through interplanetary space. Yet, the scarcity of radially aligned CME crossings restricts investigations on the evolution of CME magnetic structures to a few case studies, preventing a comprehensive understanding of CME complexity changes during propagation. In this paper, we perform numerical simulations of CMEs interacting with different solar wind streams using the linear force-free spheromak CME model incorporated into the EUropean Heliospheric FORecasting Information Asset (EUHFORIA) model. The novelty of our approach lies in the investigation of the evolution of CME complexity using a swarm of radially aligned, simulated spacecraft. Our scope is to determine under which conditions, and to what extent, CMEs exhibit variations of their magnetic structure and complexity during propagation, as measured by spacecraft that are radially aligned. Results indicate that the interaction with large-scale solar wind structures, and particularly with stream interaction regions, doubles the probability to detect an increase of the CME magnetic complexity between two spacecraft in radial alignment, compared to cases without such interactions. This work represents the first attempt to quantify the probability of detecting complexity changes in CME magnetic structures by spacecraft in radial alignment using numerical simulations, and it provides support to the interpretation of multi-point CME observations involving past, current (such as Parker Solar Probe and Solar Orbiter), and future missions.