Unexpected major geomagnetic storm caused by faint eruption of a solar trans-equatorial flux rope.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39448608.
- Also identified by DOI 10.1038/s41467-024-53538-1 and PMC identifier 11502832.
- Licence recorded as CC BY-NC-ND.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Some geomagnetic storms' solar origins are ambiguous, making them hard to predict. On March 23, 2023, a severe geomagnetic storm occurred, however, forecasts based on remote-sensing observations failed to predict it. Here, we show clear evidence that this storm originates from the eruption of a trans-equatorial, longitudinal and low-density magnetic flux rope (FR) with weaker coronal emission and no chromospheric signs. The FR's gentle eruption results in a faint full-halo coronal mass ejection (CME), which is missed by forecasters and not included in CME catalogs. Combining magnetic field modeling and in-situ measurements, we reveal the FR's southward axial magnetic field as the main cause of the geomagnetic storm. This CME is the stealthiest one reported causing a severe geomagnetic storm. Our study highlights that erupting trans-equatorial FRs can generate major geomagnetic storms in a stealthy way. Characteristic observational signatures of similar eruptions are proposed to help in future forecasts.