[IGPP Everyone] NOW: Space Physics Seminar - 12/02/2022, 3:30pm PST - Energy Transfer via the Aurora on Mesoscales: Energy Flux, Average Energy, and Hall Auroral Conductance from THEMIS All-Sky-Imagers, by: Christine E. Gabrielse PhD

[Emmanuel Masongsong]

As a reminder: This will be the last Seminar of the Quarter! 



SPACE PHYSICS SEMINAR 

DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES 

DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES 
UNIVERSITY OF CALIFORNIA, LOS ANGELES 

Friday, December 2nd, 2022 
3:30 - 4:30 PM 

In-person in Slichter 3853, with refreshments afterwards on Franz Patio 

Energy Transfer via the Aurora on Mesoscales: Energy Flux, Average Energy, and Hall Auroral Conductance from THEMIS All-Sky-Imagers 




Christine E. Gabrielse PhD 
Research Scientist at The Aerospace Corp. 

El Segundo, CA 





Abstract: 





Recent attention has been given to mesoscale phenomena across geospace ( ∼ 10 s km to 500 km in the ionosphere or ∼ 0.5 RE to several RE in the magnetosphere), as their contributions to the system global response are important yet remain uncharacterized mostly due to limitations in data resolution and coverage as well as in computational power. One example of a major gap in understanding is how the high latitude ionosphere-thermosphere system responds to “forcing from above”—that is, magnetospheric drivers such as precipitation—which occurs on mesoscales but is modeled on global scales. To answer that, we need to understand how much energy is deposited from the magnetosphere on various scale sizes. This talk describes a new method that utilizes the 2D array of Time History of Events and Macroscale Interactions during Substorms (THEMIS) white-light all-sky-imagers (ASI), in conjunction with meridian scanning photometers, to estimate the auroral scale sizes of intense precipitating energy fluxes and the associated Hall conductances. We investigated the role of precipitated energy flux and average energy on mesoscales as contrasted to large-scales for two back-to-back substorms, finding that mesoscale aurora contributes up to ∼ 80% ( ∼ 60%) of the total energy flux immediately after onset during the early expansion phase of the first (second) substorm, and continues to contribute ∼ 30–55% throughout the remainder of the substorm. Using the measured energy flux and tables produced from the Boltzmann Three Constituent (B3C) auroral transport code (Strickland et al., 1976; 1993), we also estimated the 2D Hall conductance and compared it to Poker Flat Incoherent Scatter Radar conductance values, finding good agreement for both discrete and diffuse aurora. The talk also discusses examples of how these data products are being used to enhance global models and contribute to NASA GDC efforts. 





Zoom link: https://ucla.zoom.us/j/98070654630?pwd=aWdrSktueG9xWjU3cDZiQUhGRXV0UT09 





In-Charge: Andrei Runov 




Fall Space Physics Seminar schedule: 





December 2, 2022 - Christine Gabrielse-Lin, Aerospace Corp. 
Estimating Precipitating Energy Flux, Average Energy, and Hall Auroral Conductance From THEMIS All-Sky-Imagers With Focus on Mesoscales 






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