Thursday, April 04, 2019 at 4:00 PM

JILA Auditorium

Toshi Nishimura, Boston University

"Multi-scale Dynamics in Geospace Revealed by Optical Measurements"

Abstract:

Aurora, optical emissions in the upper polar atmosphere, reflects a variety of space phenomena, and offers an opportunity for remote sensing of the space environment. Processes associated with aurora are not only important for Space Physics but also impact the human society such as radio communication and satellite operation during large space weather events. Recent studies have shown that localized structures in the Geospace system have major impacts on mass, momentum and energy transport in the system. However, efforts for understanding their quantitative properties and formation processes are severely limited due to difficulties in resolving those structures.

This talk will firstly introduce a few examples of multi-scale processes, and then present recent progresses on the following three questions from the auroral research perspective: (1) What is the quantitative nature of multi-scale energy deposition from space to the upper atmosphere? (2) What is the physics of precursors to auroral breakup? (3) What is the possible energy source of structured auroral arcs at subauroral latitudes? Results from auroral imaging, radars and satellites emphasize that transient flows from dayside to nightside are important for driving nightside aurora. This sequence provides a possibility of predicting nightside auroral responses much earlier than possible previously. Finally, we will discuss future directions toward understanding multi-scale processes during space weather events.

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