Large-scale waves in the neutral atmosphere have been observed to propagate from the lower atmosphere through the upper atmosphere. Corresponding wave structures in the plasma have been observed throughout the low-latitude ionosphere, observed to reach heights of 500 miles. ICON will resolve fundamental questions about the coupling mechanisms between these two regions that drive similar-scale wave patterns and quantify the relative importance of (1) changes in the wind-driven electrodynamics; (2) changes in the conductivity; (3) changes in neutral composition; and (4) direct forcing of the ionosphere by those large-scale atmospheric waves that propagate all the way to the upper ionospheric altitudes.

Remarkable changes in the ionosphere and upper atmosphere occur at low latitudes in response to disturbances in the solar wind. The electric field induced by the solar wind directly competes with internal drivers (Science Questions 1 and 2) and dynamo fields driven by storm-time neutral winds. Without comprehensive measurements of all the local drivers and the response of the ionosphere/thermosphere system, we depend upon numerical models to best understand the effects of these competing processes. ICON will provide the set of measurements that will allow for the first time a complete separation of internal “wind/wave-dominated” forcing from external “storm-driven” disturbance processes to understand how these processes interact to form the response of our ionosphere to storm inputs.