Ionosphere-thermosphere (IT) response to solar wind forcing during magnetic storms

Abstract

During magnetic storms, there is a strong response in the ionosphere and thermosphere which occurs at polar latitudes. Energy input in the form of Poynting flux and energetic particle precipitation, and energy output in the form of heated ions and neutrals have been detected at different altitudes and all local times. We have analyzed a number of storms, using satellite data from the Defense Meteorological Satellite Program (DMSP), the Gravity Recovery and Climate Experiment (GRACE), Gravity field and steady-state Ocean Circulation Explorer (GOCE), and Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission. Poynting flux measured by instruments on four DMSP spacecraft during storms which occurred in 2011-2012 was observed in both hemispheres to peak at both auroral and polar latitudes. By contrast, the measured ion temperatures at DMSP and maxima in neutral density at GOCE and GRACE altitudes maximize in the polar region most frequently with little evidence of Joule heating at auroral latitudes at these spacecraft orbital locations.

Scientific challenges in thermosphere-ionosphere forecasting – conclusions from the October 2014 NASA JPL community workshop

“…The role of energy deposition during geomagnetic storms has recently been studied using satellite observations of electromagnetic and neutral density perturbations (Huang et al 2014(Huang et al , 2016. Energy deposition in the polar cap, versus auroral latitudes, is found to be a significant and possibly dominant phenomenon during storms, with major implications for global thermosphere circulation patterns and the evolution of ionospheric storms.…”

“…As shown by Huang et al (2016), the thermospheric densities respond rapidly to the onset of magnetic activity. This response is exhibited as transient localized maxima in neutral density that we interpret as evidence of localized Joule heating.…”

“…Huang et al (2014 andHuang et al 2016, this issue) discuss new findings which show that the polar cap is a location of significant energy input. However, community models are not sufficiently developed to capture significant amounts of energy entering through these ''open'' field lines.…”

“…We have carried out a statistical analysis of neutral density maxima that occur at high latitudes as a result of energy deposition due to Poynting flux and energetic particle precipitation (Huang et al 2016, this issue; see Figure 11). As shown by Huang et al (2016), the thermospheric densities respond rapidly to the onset of magnetic activity.…”

GOCE Gradiometer Measurements Response to Ionospheric Dynamics

“…Moreover, there are numerous recent publications that use GOCE‐derived thermospheric neutral winds also referred in the literature as “crosswinds” and air density profiles for further understanding of thermospheric‐ionospheric studies as well as for model evaluation and assessment purposes (Doornbos et al, ; Drob et al, ; Lu et al, ). For the density retrieval and cross‐track neutral winds derived from previous dedicated gravity missions, namely CHAllenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE), the reader is referred to Bruinsma and Biancale (), Bruinsma et al (), Doornbos et al (), Forbes et al (), Förster et al (), Huang et al (), Lühr et al (), and Sutton et al ().…”