GP014-0007
On the Role of Convection in Driving Intense Geomagnetic Disturbances on the Flanks of the Magnetosphere During Magnetic Storms

Wednesday, 16 December 2020
Poster
Stavros Dimitrakoudis1, Ian Robert Mann2, Ivan Pakhotin1, Daniel T Welling3, Leonid Olifer1, David K Milling1, Andy Kale1 and Akimasa Yoshikawa4, (1)University of Alberta, Edmonton, AB, Canada, (2)University of Alberta, Department of Physics, Edmonton, AB, Canada, (3)University of Texas at Arlington, Arlington, TX, United States, (4)Kyushu University, Faculty of Science, Fukuoka, Japan
Abstract:
Geomagnetically induced currents (GIC) correlate with high and sustained rates of change of magnetic field measurements on the ground (dB/dt), which can be caused by various types of geomagnetic disturbances (GMD). During the geomagnetic storms of 17 March 2015 and 8 September 2017 we observed extremely similar and very large dB/dt events on the flanks that correspond to local time regions not associated with commonly considered drivers of large GMD. Comparisons to global MHD simulations indicate that the driving physics may also not be captured such that the GMD are thus not reproduced by some current MHD models. From analysing their spatio-temporal profiles in conjunction with the behaviour of the interplanetary magnetic field through various ground and space observations, including a Swarm spacecraft conjunction with ground stations, we can piece together a picture of strong convection as a driver for very large dB/dt and hence GICs in the dawn and dusk local time sectors of the magnetosphere during strong geomagnetic storms.
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