Determine the Large-Height Evolution of the 2024 March 29 CME Angular Width

Determine whether the angular width of the 2024 March 29 CME genuinely stabilizes near unity at larger heliocentric heights or continues to evolve beyond the available METIS field of view.

Background

The paper measures CME angular width as a function of heliocentric height to compare global expansion with the separately determined radial self-similarity coefficients of the CME front and core. For the 2024 March 29 event, the normalized angular width approaches unity only at the outer edge of the available METIS field of view. Because observations do not extend sufficiently far beyond that point, it remains unresolved whether the angular width has reached a genuine saturation regime or would continue increasing at larger heights. Resolving this issue requires observations covering greater heliocentric distances and a larger event sample for systematic comparison.

References

In the 2024-03-29 event, the angular width approaches unity only at the very edge of the available METIS FOV, so we cannot confirm whether it has genuinely stabilised or would continue to evolve at larger heights.

— CME Kinematics with Optical Flow: Multi-Coronagraph Insights into Internal Velocity Dispersion  (2609.25904 - Das et al., 22 Sep 2026) in Section 5.4, “Evaluating Radial Self-Similar Expansion in CME Front and Core”