DYNAMIC — Mission Concept to Reveal Critical Link Between Earth’s Atmosphere and Space

Our ability to predict the effects of space weather of the near-Earth space environments hinges on understanding the lower thermosphere and ionosphere (LTI) altitude region, where the thermosphere's neutral gas strongly interacts with the coexisting plasma population of the ionosphere. This altitude region is a convergence point of atmospheric wave forcing from below and solar and magnetospheric forcing above. Plasma-neutral interaction and atmospheric dynamical processes occurring in the LTI give rise to remarkably rich, yet poorly understood, multi-scale phenomena that have significant influences on radio communication, navigation, positioning, and satellite operation. Acquiring in-situ measurements to bridge the knowledge gap is difficult, because these altitudes are too low for satellites and too high for balloons. Commonly used space-based remote-sensing approaches for LTI are hampered by the lack of consistent optical emission sources that are unaffected by solar illumination and auroral conditions. This paper gives an overview of a Dynamical Neutral Atmosphere-Ionosphere Coupling (DYNAMIC) mission concept that overcomes these longstanding thermospheric observational challenges using a pair of remote sensing instruments and provides a first comprehensive view of the global variability of an under-observed altitude region, where atmospheric waves driven by terrestrial weather compete with direct influence from the magnetosphere and Sun in inducing space weather disturbances. The paper also discusses how DYNAMIC, GDC and ground-based measurements together can be combined to develop a broader understanding of atmosphere-ionosphere-magnetosphere as a coupled system and space weather phenomena.