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Global Driving of Auroral Precipitation: 1. Balance of Sources
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  • Agnit Mukhopadhyay,
  • Daniel T Welling,
  • Michael W. Liemohn,
  • Aaron J. Ridley,
  • Meghan Burleigh,
  • Chen Wu,
  • Shasha Zou,
  • Hyunju K Connor,
  • Elizabeth M. Vandegriff,
  • Pauline Dredger,
  • Gabor Toth
Agnit Mukhopadhyay
University of Michigan

Corresponding Author:[email protected]

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Daniel T Welling
University of Texas at Arlington
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Michael W. Liemohn
University of Michigan-Ann Arbor
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Aaron J. Ridley
University of Michigan-Ann Arbor
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Meghan Burleigh
Naval Research Laboratory
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Chen Wu
University of Michigan-Ann Arbor
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Shasha Zou
University of Michigan-Ann Arbor
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Hyunju K Connor
University of Alaska Fairbanks
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Elizabeth M. Vandegriff
University of Texas at Arlington
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Pauline Dredger
The University of Texas at Arlington
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Gabor Toth
University of Michigan
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Abstract

The accurate determination of auroral precipitation in global models has remained a daunting and rather inexplicable obstacle. Understanding the calculation and balance of multiple sources that constitute the aurora, and their eventual conversion into ionospheric electrical conductance, is critical for improved prediction of space weather events. In this study, we present a semi-physical global modeling approach that characterizes contributions by four types of precipitation - monoenergetic, broadband, electron and ion diffuse - to ionospheric electrodynamics. The model uses a combination of adiabatic kinetic theory and loss parameters derived from historical energy flux patterns to estimate auroral precipitation from magnetohydrodynamic (MHD) quantities. It then converts them into ionospheric conductance that is used to compute the ionospheric feedback to the magnetosphere. The model has been employed to simulate the April 5 - 7, 2010 “Galaxy15” space weather event. Comparison of auroral fluxes show good agreement with observational datasets like NOAA-DMSP and OVATION Prime. The study shows a dominant contribution by electron diffuse precipitation, accounting for ~74% of the auroral energy flux. However, contributions by monoenergetic and broadband sources dominate during times of active upstream conditions, providing for up to 61% of the total hemispheric power. The study also indicates a dominant role played by broadband precipitation in ionospheric electrodynamics which accounts for ~31% of the Pedersen conductance.
Jul 2022Published in Journal of Geophysical Research: Space Physics volume 127 issue 7. 10.1029/2022JA030323