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.