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Sources of Auroral Conductance - Balance and Impacts
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  • Agnit Mukhopadhyay,
  • Daniel Welling,
  • Meghan Burleigh,
  • Michael Liemohn,
  • Aaron Ridley,
  • Elizabeth Vandegriff,
  • Shasha Zou,
  • Hyunju Connor,
  • Brian Anderson
Agnit Mukhopadhyay
University of Michigan Ann Arbor

Corresponding Author:[email protected]

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Daniel Welling
University of Texas at Arlington
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Meghan Burleigh
US Naval Research Laboratory
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Michael Liemohn
University of Michigan
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Aaron Ridley
Univ Michigan
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Elizabeth Vandegriff
University of Texas at Arlington
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Shasha Zou
University of Michigan
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Hyunju Connor
University of Alaska Fairbanks
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Brian Anderson
Johns Hopkins Univ
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Abstract

Despite significant developments in global modeling, the determination of ionospheric conductance in the auroral region remains a challenge in the space science community. With advances in adiabatic kinetic theory and numerical couplings between global magnetohydrodynamic models and ring current models, the dynamic prediction of individual sources of auroral conductance have improved significantly. However, the individual impact of these sources on the total conductance and ionospheric electrodynamics remains understudied. In this study, we have investigated individual contributions from four types of auroral precipitation - electron & ion diffuse, monoenergetic & Alfven wave-driven - on ionospheric electrodynamics using a novel modeling setup. The setup encompasses recent developments within the University of Michigan’s Space Weather Modeling Framework (SWMF), specifically through the use of the MAGNetosphere - Ionosphere - Thermosphere auroral precipitation model and dynamic two-way coupling with the Global Ionosphere-Thermosphere Model. This modeling setup replaces the empirical idealizations traditionally used to estimate conductance in SWMF, with a physics-based approach capable of resolving 3-D high-resolution mesoscale features in the ionosphere-thermosphere system. Using this setup, we have simulated an idealized case of southward Bz 5nT & the April 5-7 “Galaxy15” Event. Contributions from each source of precipitation are compared against the OVATION Prime Model, while auroral patterns and hemispheric power during Galaxy15 are compared against observations from DMSP SSUSI and the AE-based FTA model. Additionally, comparison of field aligned currents (FACs) and potential patterns are also conducted against AMPERE, SuperDARN & AMIE estimations. Progressively applying conductance sources, we find that diffuse contributions from ions and electrons provide ~75% of the total energy flux and Hall conductance in the auroral region. Despite this, we find that Region 2 FACs increase by ~11% & cross-polar potential reduces by ~8.5% with the addition of monoenergetic and broadband sources, compared to <1% change in potential for diffuse additions to the conductance. Results also indicate a dominant impact of ring current on the strength and morphology of the precipitation pattern.