JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Poster

P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM11] [EE] Mesosphere-Thermosphere-Ionosphere Coupling in the Earth's Atmosphere

Wed. May 24, 2017 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL7)

[PEM11-P11] What Drives the Electrodynamics of the Low-Latitude Evening Ionosphere?

*Arthur D Richmond1, William Evonosky2, Tzu-Wei Fang3, Astrid Maute1 (1.NCAR, 2.U. South Florida, 3.U. Colorado)

Neutral and plasma dynamics are strongly coupled in the F region. In the low-latitude evening ionosphere an eastward neutral wind is accelerated by a strong eastward horizontal pressure gradient force that is incompletely balanced by ion drag and viscosity. Plasma convection is driven mainly by the zonal neutral wind in the lower Equatorial Ionization Anomaly (EIA) region, balanced by ion-neutral collisions in the E and lower F regions. Increased night-time E-region conductivity retards both ion convection and neutral winds in the F region. Unless the E-region night-time conductivity is large, the accelerating eastward ion convection draws plasma up from lower apex heights, producing the equatorial F-region pre-reversal enhancement of vertical ion drift.