Fig. 7From: On some features characterizing the plasmasphere–magnetosphere–ionosphere system during the geomagnetic storm of 27 May 2017From the top: the Dst index, the kp index and the equatorial plasma mass density at L = 5.3, 4.3 and 2.9, respectively, estimated from ULF frequencies obtained from the three EMMA station pairs MUO–RAN, RAN–HAN and TAR–BRZ. Values are in UTBack to article page