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Title: Formation of Continuum Emission Structures Associated With the Aurora
Abstract Recent observations enabled by improvements in geospace remote‐sensing instrumentation have revealed the spatial structure of continuum emissions that appear to be associated with the aurora, but little is known about the formation and drivers of these structures. We perform the first comprehensive statistical study of 52 auroral continuum structures identified using the Transition Region Explorer (TREx) network of broadband color all‐sky imagers and meridian imaging spectrographs. Superposed epoch analyses of global geomagnetic conditions reveal storm‐level activity and show that these structures appear statistically during the peak of geomagnetic disturbances. On average, the disturbance storm‐time index (Dst) decreases by approximately 50 nT to moderate storm levels in the 30 hr preceding emission observation, while the planetaryK(Kp) index rises from roughly 2 to 4.5. TREx optical data reveal a sharply peaked, spectrally “gray” luminosity that exceeds that of the surrounding aurora. The TREx auroral transport model indicates a surge of precipitating electron energy flux of approximately 5 erg/cm2/s spatially coincident with the structures themselves. A multi‐imager case study indicates that this enhancement is a coherent mesoscale region that tracks the visible structure. These results demonstrate that active geomagnetic conditions support the formation of these structures and suggest a direct coupling to energetic electron precipitation. Simultaneous observation of a broadband continuum enhancement with enhanced precipitation may favor a chemiluminescent nitric‐oxide continuum generation mechanism, although uncertainties remain regarding the viability of this mechanism.  more » « less
Award ID(s):
2445467
PAR ID:
10674374
Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Journal of Geophysical Research: Space Physics
Volume:
131
Issue:
3
ISSN:
2169-9380
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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