Comparison of Empirical Models of Ionospheric Heating to Global Simulations

TL;DR

This study evaluates how well empirical ionospheric heating models match detailed global simulations during geomagnetic storms, revealing discrepancies in scale factors used for Joule heating estimates.

Contribution

It compares empirical models with comprehensive simulations for multiple storms, highlighting differences in predicted Joule heating scale factors.

Findings

Empirical models' scale factors are half those predicted by SWMF simulations.

Comparison across 11 storm simulations shows quantitative differences.

Empirical models can be calibrated for better accuracy.

Abstract

Intense currents produced during geomagnetic storms dissipate energy in the ionosphere through Joule heating. This dissipation has significant space weather effects, and thus it is important to determine the ability of physics-based simulations to replicate real events quantitatively. Several empirical models estimate Joule heating based on ionospheric currents using the AE index. In this study, we select 11 magnetic storm simulations from the CCMC database and compare the integrated Joule heating in the simulations with the results of empirical models. We also use the SWMF global magnetohydrodynamic simulations for 12 storms to reproduce the correlation between the simulated AE index and simulated Joule heating. We find that the scale factors in the empirical models are half what is predicted by the SWMF simulations.