Frequency of Strongly Distorted Interplanetary Coronal Mass Ejections

Determine how frequently interplanetary coronal mass ejections exhibit strong global distortions of their embedded magnetic flux rope geometry, such that the local axis orientation varies substantially between spatially separated in situ observations (e.g., at Wind and STEREO-A), as indicated by multi-point reconstructions using the Distorted Magnetic Flux Rope model.

Background

The paper introduces a fully analytic Distorted Magnetic Flux Rope (DMFR) model that allows for arbitrary distortions of both the cross-section and the magnetic axis, aiming to better capture complex ICME geometries than traditional cylindrical or toroidal models.

Applying DMFR to an April 2023 ICME observed by Wind and STEREO-A, the authors find notably different local flux rope axis orientations at the two spacecraft, suggesting a globally distorted (inverse V-shaped) ICME structure. While single-point reconstructions and a multi-point attempt support this distortion, the dataset of such events is limited.

Because large-scale distortions can lead to significantly different local orientations and potentially affect space weather forecasting (e.g., Bz prediction), quantifying how often such strongly distorted ICME geometries occur is important but presently unresolved.