Chapman conference: Particle Precipitation: Drivers, Properties, and Impacts on Atmosphere, Ionosphere, Magnetosphere (AIM) Coupling – Feb 2025 at RMIT in Melbourne, AU

Energetic particle precipitation (EPP) is one of the fundamental drivers of space weather in the coupled atmosphere-ionosphere-magnetosphere (AIM) system. These electrons and ions from the sun or the terrestrial magnetosphere, ranging in energy from hundreds of eV to GeV, precipitate into the atmosphere in response to enhanced topside (solar and magnetosphere) driving. They deposit their energy at a wide range of altitudes, enhancing ionization, and changing neutral temperature, density, and winds. During times of prolonged driving the resulting changes can adversely affect anthropogenic systems including disruption of communication and power systems, and increased satellite drag leading to orbital decay. In addition to its effects on space weather, EPP has been recognized as an important component of climate via its ability to indirectly destroy ozone, modifying local radiative balance in the middle and upper atmosphere. Despite the recognized importance of EPP to the AIM system, the way in which these two-way coupled systems interact is highly complex and remains poorly understood and constrained. Measurements from our current observational fleet are not able to fully capture EPP-driven AIM dynamics. As a result, we lack a fundamental understanding of many aspects of this coupled system, and models cannot be validated and are inhibited in their ability to forecast space weather. To compound this situation, different aspects of the AIM system are studied by the different communities with insufficient cross-community cooperation. Properly studying AIM dynamics, a societal level priority, requires a global systems science (holistic) approach to data collection, analysis, and modeling. This Chapman conference will bring together participants from the AIM communities to focus efforts on identifying and communicating outstanding issues, how models can bridge knowledge gaps, promising techniques for enhanced analysis, and required new types of observations.