Overview
- The coronal mass ejection observed on August 5, 2024 produced simultaneous red- and blue-shifted spectral features that showed parts of the eruption moving toward and away from the observer in the low corona.
- Those opposing Doppler signatures came from VELC, the Visible Emission Line Coronagraph on Aditya‑L1, which measures line-of-sight plasma speed by shifts in coronal emission lines.
- Researchers fed the VELC spectra and NASA SDO images into three-dimensional models and found that a uniformly expanding, symmetric CME could not reproduce the observations while a tilted, uneven lateral expansion did match the data.
- Because an early asymmetric shape can change how a CME interacts with the solar wind and the drag it experiences, the result could alter speed and arrival-time estimates for storms that threaten satellites, communications and power systems.
- Aditya‑L1, launched to Sun–Earth L1 in September 2023, has delivered this mission-unique single-vantage technique and the team plans to apply it to more eruptions to test whether it can be used operationally to improve space-weather forecasts.