Rakesh Sarma¹, George John Wilkie^1,2, Enrico Camporeale^1,3, Alexander Drozdov⁴ and Yuri Shprits⁵, (1)Centrum Wiskunde & Informatica, Amsterdam, Netherlands, (2)Princeton Plasma Physics Laboratory, Princeton, United States, (3)University of Colorado, Cooperative Institute for Research in Environmental Sciences, Boulder, United States, (4)University of California Los Angeles, Los Angeles, CA, United States, (5)GFZ German Research Centre for Geosciences, Potsdam, Germany