Physics Dept Seminar

April 19, Tuesday (*SPECIAL DAY*)

Magnetosphere-Ionosphere Coupling via Electron Precipitation

Dr. Xiao-Jia Zhang,

Dept of Earth, Planetary, and Space Sciences, UCLA

(Solar & Terrestrial Physics, Host: Gerrard)

*SPECIAL TIME: 2:45 pm - 3:45 pm with 2:30 pm teatime

Room: ECE 202

Earth’s magnetosphere, the plasma environment of our planet, is shaped by solar wind flow interacting with Earth’s dipole magnetic field. Dynamics of the magnetosphere (such as geomagnetic storms and substorms) are significantly controlled by the magnetosphere-ionosphere coupling, which involves energy and mass exchanges between hot, rarified magnetospheric plasma and cold, dense ionospheric plasma. One important process for this coupling is energetic electron precipitation into the ionosphere, as driven by resonant wave-particle interactions in the magnetosphere. The precipitating flux intensity, typically modelled using inputs from high-altitude, equatorial spacecraft measurements, dictates the energy input to the atmosphere and the strength of space-atmosphere coupling. Although several theoretical mechanisms have been proposed for energetic electron precipitation, prior works lack direct experimental support. This presentation shows how we address this problem using new, low-altitude observations.