Auroral Energy Flux and Joule Heating Derived From Global Maps of Field‐Aligned Currents
| Autor: | L. J. Zanetti, R. M. Robinson |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
010504 meteorology & atmospheric sciences Energy flux Magnetosphere auroral energy input 010502 geochemistry & geophysics 01 natural sciences Physics::Geophysics Substorm Research Letter Magnetospheric Physics Ionosphere Current Systems Ring current Auroral Phenomena 0105 earth and related environmental sciences Geomagnetic storm Solar Physics Astrophysics and Astronomy Substorms Magnetic energy Magnetic Storms and Substorms geomagnetic storms Joule heating Auroral Ionosphere Field‐aligned Currents and Current Systems auroral substorms Energetic Particles: Precipitating Auroral energy flux Computational physics Interplanetary Physics Magnetic Storms Geophysics Earth's magnetic field ring current Physics::Space Physics General Earth and Planetary Sciences Space Weather Space Sciences Coronal Mass Ejections Natural Hazards |
| Zdroj: | Geophysical Research Letters |
| ISSN: | 1944-8007 0094-8276 |
| Popis: | We calculate auroral energy flux and Joule heating in the high‐latitude ionosphere for 27 geomagnetically active days using two‐dimensional maps of field‐aligned currents determined by the Active Magnetosphere and Planetary Response Experiment. The energy input to the ionosphere due to Joule heating increases more rapidly with geomagnetic activity than that due to precipitating particles. The energy flux varies more smoothly with time than Joule heating, which is impulsive in nature on time scales from minutes to tens of minutes. These impulsive events correlate well with recoveries in the Sym‐H index, with the maximum correlation when compared to Sym‐H recoveries 70 min later. Because of prior studies that have associated transient recoveries of Sym‐H with substorm expansions, the delay found here suggests that dissipation of energy in the ionosphere occurs during the substorm growth phase prior to the release of magnetic energy caused by diversion of tail currents. Key Points We calculate hemispherically integrated precipitating particle energy fluxes and Joule heating from global maps of field‐aligned currentsEnergy input from Joule heating and precipitating particles correlates well with increases in the Sym‐H index occurring about 1 h laterJoule heating in the ionosphere during substorm growth phase is approximately equal to magnetic energy released during substorm expansion |
| Databáze: | OpenAIRE |
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