Dayside global ionospheric response to the major interplanetary events of October 29–30, 2003 “Halloween Storms”

We demonstrate extreme ionospheric response to the large interplanetary electric fields during the “Halloween” storms that occurred on October 29 and 30, 2003. Within a few (2–5) hours of the time when the enhanced interplanetary electric field impinged on the magnetopause, dayside total electron content increases of ∼40% and ∼250% are observed for the October 29 and 30 events, respectively. During the Oct 30 event, ∼900% increases in electron content above the CHAMP satellite (∼400 km altitude) were observed at mid‐latitudes (±30 degrees geomagnetic). The geomagnetic storm‐time phenomenon of prompt penetration electric fields is a possible contributing cause of these electron content increases, producing dayside ionospheric uplift combined with equatorial plasma diffusion along magnetic field lines to higher latitudes, creating a “daytime super‐fountain” effect.