Faster Traveling Atmosphere Disturbances Caused by Polar Ionosphere Turbulence Heating

Wednesday, February 28, 2018

For the first time, a new module enables Jing Liu and others to investigate the intimate coupling between polar turbulence electron heating and thermosphere disturbances in the context of a first principle, self-consistent model. The model includes both the turbulence electron heating and the electronneutral cooling rate correction associated with the Farley-Buneman Instability (FBI)—Thermosphere Ionosphere Electrodynamics Global Circulation Model (TIEGCM).

Meridional wind variability image
Meridional wind variability at fixed local times on the pressure level 4.125 (~ 584 410 km). The top and middle panels are the meridional winds with and without AEH effects, respectively. Their differences are in the bottom panel.

Our simulation results show that during geomagnetic storms and after taking the FBI effects into account, Joule heating is almost doubled in the E-region at these locations of strong convection electric field. This increases by 6% the phase speed of traveling atmosphere disturbances (TADs) that are launched from both hemispheres. Additional heating sources also directly produce a divergence in the zonal wind in the lower thermosphere. However, the FBI impact on the thermosphere at F-region altitudes is not so straightforward. E-region anomalous electron heating in association with the FBI can change the phase speeds and magnitudes of TADs from high latitudes in both hemispheres, and consequently modify global neutral wind circulation at F-region altitudes. This, in turn, can affect the neutral temperature through adiabatic compressional heating and expansive cooling. This study demonstrates how the ionosphere thermosphere physical processes across different temporal and spatial scales are tightly coupled together throughout the whole upper atmosphere domain.

Publication Name: JGR-Space Physics