Abstract
We report on features of solar wind-magnetosphere coupling elicited by shocks propagating through coronal mass ejections (CMEs) by analyzing the intense geomagnetic storm of 6 August 1998. During this event, the dynamic pressure enhancement at the shock combined with a simultaneous increase in the southward component of the magnetic field resulted in a large earthward retreat of Earth's magnetopause, which remained close to geosynchronous orbit for more than 4 h. This occurred despite the fact that both shock and CME were weak and relatively slow. Another similar example of a weak shock inside a slow CME resulting in an intense geomagnetic storm is the 30 September 2012 event, which strongly depleted the outer radiation belt. We discuss the potential of shocks inside CMEs to cause large geomagnetic effects at Earth, including magnetopause shadowing.
Department
Physics, Coronal Mass Ejection Research Group
Publication Date
7-15-2015
Journal Title
Geophysical Research Letters
Publisher
American Geophysical Union Publications
Digital Object Identifier (DOI)
10.1002/2015GL064530
Document Type
Article
Recommended Citation
Lugaz, N., C. J. Farrugia, C.-L. Huang, and H. E. Spence (2015), Extreme geomagnetic disturbances due to shocks within CMEs. Geophys. Res. Lett., 42, 4694–4701. doi: 10.1002/2015GL064530.