Physics Dept Seminar

June 4, Wednesday (*SPECIAL DAY*)

Solar Eclipses and Coincidental Substorms

Dr. Shane Coyle

Virginia Tech

(Space Physics, Host: Hyomin Kim)

Room: ECE 202

Time: 2:15 pm - 3:15 pm with 2 pm teatime (**SPECIAL TIME**)

Solar eclipses offer a unique opportunity to observe the effects of ionospheric electrodynamics on the magnetosphere, largely isolated from other well-known seasonal factors. Despite extensive research, the precise conditions that lead to geomagnetic substorm onset remain incompletely understood. A case study of the 2021 Antarctic solar eclipse is presented and establishes the need for a more comprehensive statistical study. We then apply a mutual information analysis in a follow-on study to compare previously documented substorm onsets with solar eclipses over the past two decades. Our findings indicate a statistically significant correlation between the two, suggesting that their co-occurrence is more likely than random chance would predict. One possible explanation is that rapid changes in ionospheric conductivity during an eclipse may alter magnetospheric conditions in a way that promotes substorm initiation. Although the underlying mechanism is still unclear, our results provide compelling evidence of a connection between solar eclipses and substorm activity.