Whitepaper #055 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional topics: system science; user-need-driven basic space weather research.
Electromagnetic energy is likely the largest unknown input to the upper atmosphere. Together with precipitating particles, it may constitute the largest overall source of energy during geomagnetic storms. This source of energy is a critical driver of stormtime dynamics, and is responsible for plasma convection, atmospheric upwelling in the cusps, as well as many other important phenomena.