Drivers and Impacts of Diffuse Auroral Precipitation
 

The discovery of space currents and charged particles streaming down the Earth's magnetic field has reshaped our understanding of auroras since the dawn of space exploration in the 1960s. These precipitating charged particles, depending on how they are energized, produce either discrete or diffuse auroras. Diffuse auroral precipitation, with a total power exceeding 25 GW, contributes over 75% of the global particle energy flux input into the ionosphere-thermosphere system, making it a major driver of upper atmospheric dynamics. Recent advancements in observations and modeling have provided new insights into the physical processes generating diffuse auroral precipitation, i.e., electron pitch-angle scattering by wave particle interactions in the magnetosphere. The first part of this talk will discuss the key wave modes producing diffuse auroral precipitation, with a focus on the newly identified contributor--- time domain structures (TDS), the smallest (Debye-scale) yet universal nonlinear plasma structures in the magnetosphere. The second part of this talk will examine the impact of dynamic diffuse auroral precipitation on the ionosphere-thermosphere system, including auroral ionosphere heating, conductivity variations, and plasma density structuring.