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JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 111,
A07S01,
25 PP., 2006
doi:10.1029/2005JA011273
Corotating solar wind streams and recurrent geomagnetic activity: A review
Jet Propulsion Laboratory, Pasadena, California, USA
Instituto Nacional Pesquisas Espaciais (INPE), Sao Jose dos Campos, Sao Paolo, Brazil
Instituto Nacional Pesquisas Espaciais (INPE), Sao Jose dos Campos, Sao Paolo, Brazil
Instituto Nacional Pesquisas Espaciais (INPE), Sao Jose dos Campos, Sao Paolo, Brazil
NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Planets and Magnetospheres Group, Rutherford Appleton Laboratory, Oxfordshire, UK
Solar-Terrestrial Environment Laboratory, Nagoya University, Toyokawa, Japan
Department of Information and Systems Engineering, Kanazawa University, Kanazawa, Japan
High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colorado, USA
Department of Physics, University of Alberta, Edmonton, Alberta, Canada
Institute of Geophysics and Planetary Physics, University of California at Los Angeles, Los Angeles, California, USA
Department of Physics and Technology, University of Bergen, Bergen, Norway
Max Planck Institute for Solar System Research, Lindau, Germany
Solar wind fast streams emanating from solar coronal holes cause recurrent, moderate intensity geomagnetic activity at Earth. Intense magnetic field regions called Corotating Interaction Regions or CIRs are created by the interaction of fast streams with upstream slow streams. Because of the highly oscillatory nature of the GSM magnetic field z component within CIRs, the resultant magnetic storms are typically only weak to moderate in intensity. CIR-generated magnetic storm main phases of intensity Dst < −100 nT (major storms) are rare. The elongated storm “recovery” phases which are characterized by continuous AE activity that can last for up to 27 days (a solar rotation) are caused by nonlinear Alfven waves within the high streams proper. Magnetic reconnection associated with the southward (GSM) components of the Alfvén waves is the solar wind energy transfer mechanism. The acceleration of relativistic electrons occurs during these magnetic storm “recovery” phases. The magnetic reconnection associated with the Alfvén waves cause continuous, shallow injections of plasma sheet plasma into the magnetosphere. The asymmetric plasma is unstable to wave (chorus and other modes) growth, a feature central to many theories of electron acceleration. It is noted that the continuous AE activity is not a series of substorm expansion phases. Arguments are also presented why these AE activity intervals are not convection bays. The auroras during these continuous AE activity intervals are less intense than substorm auroras and are global (both dayside and nightside) in nature. Owing to the continuous nature of this activity, it is possible that there is greater average energy input into the magnetosphere/ionosphere system during far declining phases of the solar cycle compared with those during solar maximum. The discontinuities and magnetic decreases (MDs) associated with interplanetary Alfven waves may be important for geomagnetic activity. In conclusion, it will be shown that geomagnetic storms associated with high-speed streams/CIRs will have the same initial, main, and “recovery” phases as those associated with ICME-related magnetic storms but that the interplanetary causes are considerably different.
Received 16 June 2005; accepted 16 December 2005; published 29 June 2006.
Citation: (2006), Corotating solar wind streams and recurrent geomagnetic activity: A review, J. Geophys. Res., 111, A07S01, doi:10.1029/2005JA011273.
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