Supersubstorms during strong magnetic storm on 7 September 2017 Irina Despirak, Natalia Kleimenova, Liudmila Gromova, Sergey Gromov and Liudmila Malysheva E3S Web Conf., 127 (2019) 01010 Published online: 05 November 2019 DOI: 10.1051/e3sconf/201912701010