Dartmouth Events

Engineering-Physics Space Plasma Seminar

Keisuke Hosokawa presents: "Multiple time-scale beats in aurora: Precise orchestration via magnetospheric chorus waves"

Tuesday, January 26, 2021
4:00pm – 5:00pm
Intended Audience(s): Public
Categories: Lectures & Seminars

Zoom link

The brightness of aurorae in Earth’s polar region often beats with periods ranging from sub-second to a few tens of a second. Past observations showed that the beat of the aurora is composed of a superposition of two independent periodicities that co-exist hierarchically. However, the origin of such multiple time-scale beats in aurora remains poorly understood due to a lack of measurements with sufficiently high temporal resolution.

By coordinating experiments using ultrafast auroral imagers deployed in the Arctic (Scandinavia and Alaska) with the newly-launched Japanese satellite "Arase", we succeeded in identifying an excellent agreement between the beats in aurorae and intensity modulations of natural electromagnetic waves in space called “chorus”. In particular, sub-second scintillations of aurorae are precisely controlled by fine-scale chirping rhythms in chorus. The observation of this striking correlation demonstrates that resonant interaction between energetic electrons and chorus waves in magnetospheres orchestrates the complex behavior of aurora on Earth and other magnetized planets.

For more information, contact:
Simon Shepherd

Events are free and open to the public unless otherwise noted.