Substorm driven chorus waves: Decay timescales and implications for pulsating aurora

Troyer, R.N.; Jaynes, A.N.; Hartley, D.P.; Meredith, N.P. ORCID: https://orcid.org/0000-0001-5032-3463; Hua, M.; Bortnik, J.. 2024 Substorm driven chorus waves: Decay timescales and implications for pulsating aurora. Journal of Geophysical Research: Space Physics, 129 (1), e2023JA031883. 13, pp. 10.1029/2023JA031883

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Text (Open Access) ©2024. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. JGR Space Physics - 2024 - Troyer - Substorm Driven Chorus Waves Decay Timescales and Implications for Pulsating Aurora.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (1MB) | Preview

Abstract/Summary

Energetic electron precipitation (EEP) associated with pulsating aurora can transfer greater than 30 keV electrons from the outer radiation belt region into the upper atmosphere and can deplete atmospheric ozone via collisions that produce NOx and HOx molecules. Our knowledge of exactly how EEP occurs is incomplete. Previous studies have shown that pitch angle scattering between electrons and lower-band chorus waves can cause pulsating aurora associated with EEP and that substorms play an important role. In this work, we quantify the timescale of chorus wave decay following substorms and compare that to previously determined timescales. We find that the chorus decay e-folding time varies based on magnetic local time (MLT), magnetic latitude, and wave frequency. The shortest timescales occur for lower-band chorus in the 21 to 9 MLT region and compares, within uncertainty, to the energetic pulsating aurora timescale of Troyer et al. (2022, https://doi.org/10.3389/fspas.2022.1032552) for energetic pulsating aurora. We are able to further support this connection by modeling our findings in a quasi-linear diffusion simulation. These results provide observations of how chorus waves behave after substorms and add additional statistical evidence linking energetic pulsating aurora to substorm driven lower-band chorus waves.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2023JA031883
ISSN:	2169-9380
Additional Keywords:	pulsating aurora; chorus wave; lower band chorus; substorm; decay timescale; energetic electron precipitation
Date made live:	08 Jan 2024 14:45 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/536600

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