The global mapping of electron precipitation and ionospheric conductance from whistler-mode chorus waves

Gillespie, Dillon; Connor, Hyunju Kim; Ma, Qianli; Zhang, Xiao-Jia; Shen, Xiao-Chen; Ozturk, Dogacan; Meredith, Nigel P. ORCID: https://orcid.org/0000-0001-5032-3463. 2024 The global mapping of electron precipitation and ionospheric conductance from whistler-mode chorus waves. Frontiers in Astronomy and Space Sciences, 11, 1442009. 15, pp. 10.3389/fspas.2024.1442009

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Text (Open Access) © 2024 Gillespie, Connor, Ma, Zhang, Shen, Ozturkand and Meredith. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. fspas-2-1442009.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (80MB) | Preview

Abstract/Summary

Auroral precipitation is the second major energy source after solar irradiation that ionizes the Earth’s upper atmosphere. Diffuse electron aurora caused by wave-particle interaction in the inner magnetosphere (L < 8) takes over 60% of total auroral energy flux, strongly contributing to the ionospheric conductance and thus to the ionosphere-thermosphere dynamics. This paper quantifies the impact of chorus waves on the diffuse aurora and the ionospheric conductance during quiet, medium, and strong geomagnetic activities, parameterized by AE <100, 100 < AE < 300, and AE > 300, respectively. Using chorus wave statistics and inner-magnetosphere plasma conditions from Timed History Events and Macroscale Interactions during Substorms (THEMIS) observations, we directly derive the energy spectrum of diffuse electron precipitation under quasi-linear theory. We then calculate the height-integrated conductance from the wave-driven aurora spectrum using the electron impact ionization model of Fang et al. (Geophys. Res. Lett., 2010, 37) and the MSIS atmosphere model. By utilizing Fang’s ionization model, the US Naval Research Laboratory Mass Spectrometer and Incoherent Scattar Radar (NRLMSISE-00) model from 2000s for the neutral atmosphere components, and the University of California, Los Angeles (UCLA) Full Diffusion Code, we improve upon the standard generalization of Maxwellian diffuse electron precipitation patterns and their resulting ionosphere conductance. Our study of global auroral precipitation and ionospheric conductance from chorus wave statistics is the first statistical model of its kind. We show that the total electron flux and conductance pattern from our results agree with those of Ovation Prime model over the pre-midnight to post-dawn sector as geomagnetic activity increases. Our study examines the relative contributions of upper band chorus (UBC) and lower band chorus wave (LBC) driven conductance in the ionosphere. We found LBC waves drove diffuse electron precipitation significantly more than UBC waves, however it is possible that THEMIS data may have underestimated the upper chorus band wave observations for magnetic latitudes below 65 ° .

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.3389/fspas.2024.1442009
ISSN:	2296-987X
Additional Keywords:	diffuse auroral precipitation, chorus wave distributions, ionospheric conductance, conductance, wave driven precipitation, diffuse electron aurora
Date made live:	20 Dec 2024 10:02 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/538585

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