Whitepaper #300 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional topics: planetary ionospheres / upper atmospheres; space-based missions/projects; system science.
We reiterate on the urgent need for global wind measurements in the ~100-250 km region with at least four but preferably six local times per days. This would transform our understanding of how the magnetic control of ion-neutral interactions produces variability in the thermosphere, and how lower atmosphere and solar/geomagnetic forcing work together to produce quiet and storm time space weather.