The Night the Ionosphere Blew Away
Abstract
We describe effects of the Interplanetary Coronal Mass Ejection (ICME) disturbance of 28-29 May 2010 on the nightside equatorial ionosphere. On 28 May the north-south component of the interplanetary magnetic field (IMF BZ) rotated from + 9 nT at 18:00 UT, to -10 nT at 21:00 UT. Over the following 12 hours IMF BZ continued to decrease reaching -18 nT before slowly recovering, then turning strongly positive at 22:00 UT on 29 May. Prior to the ICME-induced disturbance the nightside ionosphere was marked by irregularities confined to post-midnight local times, typical of the present deep solar minimum. Measured ambient plasma densities were ~104 cm-3 outside of equatorial plasma bubbles (EPBs). Subsequent to the ICME impact, the severity of the EPBs intensified then coalesced to form an ionization trench extending 50o in longitude above Africa, in which plasma densities fell below 10 cm-3, near the sensitivity floor of the Planar Langmuir Probe (PLP) on the C/NOFS satellite. The nightside equatorial ionosphere had literally been blown away! This event created one of the deepest plasma trenches encountered to date during the C/NOFS mission. The ionosphere remained perturbed for several days after the ICME passed. In this presentation PLP observations will be compared with predictive simulations of the AFRL physics based model (PBMod) driven by the measurements from the vector electric field instrument (VEFI) on C/NOFS. Complementary measurements from DMSP spacecraft as well as ground-based ionosondes and scintillation receivers will be used to formulate a comprehensive understanding of interactions revealed in this event.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMSA51B1620D
- Keywords:
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- 2415 IONOSPHERE / Equatorial ionosphere