Efficiency of solar wind energy coupling to the ionosphere

• Published in: Journal of Geophysical Research: Space Physics 2012-07, Vol.117 (A7), p.np-n/a
• Main Authors: Guo, Jianpeng, Feng, Xueshang, Emery, Barbara A., Wang, Yi
• Format: Article
• Language: English
• Subjects: coupling efficiency; Earth sciences; Earth, ocean, space; Exact sciences and technology; extreme space weather; ionospheric dissipation; solar wind energy input
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2012JA017627

We present a statistical investigation into the variations of the ionospheric energy coupling efficiencies with the solar wind energy input, the interplanetary magnetic field (IMF) clock angle and the solar wind dynamic pressure. The ionospheric energy coupling efficiencies are defined as the ratios of the ionospheric energy deposition (namely auroral precipitation, Joule heating, and their total) to the solar wind energy input. We find that the ionospheric energy coupling efficiencies decrease exponentially with the solar wind energy input. Moreover, it is the same case under geomagnetic storm conditions. Our results also show that the energy coupling efficiencies are dependent on the IMF clock angle and almost independent of the solar wind dynamic pressure. These results will help us estimate and predict energy transfer from the solar wind to the thermosphere‐ionosphere system under extreme space weather conditions, particularly severe geomagnetic storms. Key Points The efficiencies decrease exponentially with the solar wind energy input The efficiencies are dependent on the IMF clock angle The efficiencies are almost independent of the solar wind dynamic pressure