The Earth's ionosphere embedded in the thermosphere is a coupled system influenced by solar and magnetospheric processes from above, as well as by upward propagating disturbances from below. This open session is suitable for contributions on all aspects of ionospheric physics. The session invites (multi)instrumental observation (e.g. ground-based optics and magnetometers, radio wave techniques, satellite and rocket in-situ), simulation and modelling studies that address the dynamics of the ionosphere, concerning transient events, plasma waves and irregularities, as well as large-scale dynamics and long-term variations. Contributions dealing with magnetospheric forcing are sought particularly in the areas of ionospheric phenomena caused by magnetospheric storms and substorms, current closure, the deposition of energy in its various forms, and the interaction of electromagnetic waves with the ionosphere. New results that focus on investigation of latitudinal, seasonal and hemispherical effects of the storms and substorms on ionosphere are especially appreciated. As for atmospheric forcing, contributions are sought that focus on atmospheric waves, wave-wave and wave-mean flow interactions, atmospheric electricity and electrodynamical coupling processes. New results on MLT feeding (wave penetration and secondary wave generation) of ionospheric disturbances and the solar effect on the vertical propagation conditions of the atmospheric waves are particularly welcome.

Many recent advances in aeronomy, space sciences, geomagnetism, and gravity arose from combining specific knowledge of these areas in interdisciplinary research. Current outstanding questions are, for example: What features of ionospheric currents do we discover when we understand the shape, strengths, and variation of the geomagnetic background field? What is the role of upward propagating atmospheric waves in energy and momentum transport into the ionosphere? Which ionospheric processes need to be better quantified to achieve complete knowledge of global core or crustal field variations? How does knowledge of the geometry of ionospheric and magnetospheric sources help in determining Earth’s conductivity in the geomagnetic field? How strongly do we need to consider Earth’s conductivity in quantifying ionospheric currents? How can we quantify and correct for ionospheric perturbations to achieve the best gravity field solutions? Finally, what can we learn about space sciences by studying ionospheric effects on geodetic measurements?

The session invites contributions on any of the subjects and in particular on results that benefit from interdisciplinary works in the areas of space science, geomagnetism, and gravity. Submissions are welcomed that contain analyses of global satellite or ground-based observations or modelling studies, including a combination of them.

The ionosphere-thermosphere (I-T) system is closely coupled with dynamics from above and below at various spatial and temporal scales. During magnetically disturbed periods, the enhanced energy and momentum depositions at high latitude affect the I-T system strongly at middle and low latitudes, causing different behaviors from the quiet-day climatological pattern. This session focuses on recent advances in understanding the ionospheric and thermospheric structures as well as their interactions at different spatial and temporal scales. Observational, theoretical, and modeling studies are welcome, that related to the penetration and dynamo electric fields, variations of neutral and ion compositions, neutral atmospheric waves (gravity waves, tides and planetary waves), travelling ionosphere/atmosphere disturbances (TID/TAD), as well as their influences on the generation and development of small-scale plasma irregularities. Studies of I-T coupling as well as the mesosphere-lower thermosphere (MLT) coupling during magnetic quiet-time are also encouraged.

This joint session invites papers that are related to the mesosphere and lower thermosphere. It addresses the topical fields of the VarSITI (Variability of the Sun and Its Terrestrial Impact) program initiated by SCOSTEP, focusing on the role of the sun and the middle atmosphere/thermosphere/ionosphere in climate (ROSMIC). Contributions studying radiation, chemistry, energy balance, atmospheric tides, planetary waves, gravity waves, neutral-ion coupling, and the interaction of the various processes involved are welcome. This includes work on model data as well as measurements from satellites and ground based platforms such as ALOMAR.

The study of the ionized and neutral atmosphere reveals to be an efficient diagnostic tool to understand the interaction among the geospheres and the impact of the solar wind on the Earth. Any variation from the expected behaviour can be helpful to identify various forcing mechanisms originated from below and above. The vertical coupling in the atmosphere involves the influence of the upper atmospheric layers on climate and the response of the ionosphere to the modification of neutral atmosphere chemistry and dynamics. An exacerbation in the space weather conditions, in turn, can cause changes in the neutral composition and in the electron density structuring. In addition, natural hazards, such as tsunami, earthquakes, thunderstorms can produce atmospheric acoustic gravity waves that result in electron density perturbations in the ionosphere.
The broad availability of instruments on board satellites and hosted at ground opens new opportunities of multi-disciplinary and multi-instruments collaboration to advance the current understanding in the field.
This session welcomes observational, theoretical, and modeling contributions on atmospheric irregularities to identify the coupling mechanisms within the atmosphere, between the atmosphere and the lithosphere, and between the atmosphere and the geospace.