Statistical Analysis of Joule Heating and Thermosphere Response During Geomagnetic Storms of Different Magnitudes

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During a geomagnetic storm, the energy deposition from magnetosphere to thermosphere through Joule heating leads to variations in the total mass density of thermosphere. In this study, measurements obtained from the Challenging Minisatellite Payload and Gravity Recovery and Climate Experiment satellites between 2002 and 2008 are used to study the response of thermospheric density during geomagnetic storms of different magnitudes inferred from the Dst index. Based on the height‐integrated Joule heating with data derived from the Defense Meteorological Satellite Program spacecraft, we statistically analyze 265 geomagnetic storm cases to study the characteristics of Joule heating distribution and its influence on thermospheric density. The results show that between thermospheric density and Joule heating during weak and moderate geomagnetic storms, the time lag is only about 0–2 hr, while the same for intense storms is 3–5 hr. This indicates that the time lag is positively correlated with the intensity of geomagnetic storms. Besides, it is found that the peak duration of Joule heating increases for more intense geomagnetic storms.