Features of the magnetic disturbance on September 7–8, 2017 by geophysical data D.V. Blagoveshchensky a , M.A. Sergeeva b,c,⇑ , P. Corona-Romero b,c a Saint-Petersburg State University of Aerospace Instrumentation, 67, Bolshaya Morskaya, Saint-Petersburg 190000, Russia b SCiESMEX, LANCE, Instituto de Geofisica, Unidad Michoacan, Universidad Nacional Autonoma de Mexico, Antigua carretera a Patzcuaro 8701, Morelia, Michoacan C.P. 58089, Mexico c CONACYT, Instituto de Geofisica, Unidad Michoacan, Universidad Nacional Autonoma de Mexico, Antigua carretera a Patzcuaro 8701, Morelia, Michoacan C.P. 58089, Mexico Received 24 October 2018; received in revised form 1 February 2019; accepted 25 March 2019 Abstract The main feature of the geomagnetic disturbance which occurred on September 7–8, 2017, was that it consisted of two consecutive magnetic storms separated in time by 13 h. It was of interest to reveal its particular features, characteristics and geomagnetic field vari- ations during both storms and the influence they had on the ionosphere. The results are as follows. The character of the development of the first storm and its impact on the Earth’s magnetosphere and ionosphere are significantly different from the character of the devel- opment and impact of the second storm. There are prominent differences in the geomagnetic field variations at different longitudes along the same latitude sector. The asymmetry of the dayside and nightside effects was revealed. The variations of the riometer absorption level, critical frequencies of the ionosphere and Total Electron Content in each considered observation point corresponded to the variations of the magnetic field at this point. Ó 2019 COSPAR. Published by Elsevier Ltd. All rights reserved. Keywords: Consecutive magnetic storms; Ionosphere; Ionospheric sounding; Absorption; TEC 1. Introduction The study of magnetic disturbances (storms and sub- storms) caused by solar events, especially the intense dis- turbances, is a part of the studies included in the Space Weather programs. Space Weather (SW) is a general term used to name the conditions changing with time within the solar-terrestrial space, in particular in the heliosphere, magnetosphere, ionosphere and thermosphere. SW can impact and can even cause the occurrence of the significant damage on space-based and ground-based systems (Cannon, 2013; Goodman, 2005). This is especially true within the context of contemporary reality of more and more susceptible electronic equipment used in different sec- tors of economy and whose not reliable operation can cause additional expenses and eventually even potential harm to human health. In addition, the valuable space developments and such sectors of national and interna- tional infrastructures like radio communication and navi- gation systems, electrical networks and aviation are extremely sensitive to SW manifestations. Therefore, the forecasting of SW and mitigation of its effects through bet- ter understanding of the physics of magnetic disturbances becomes the main requirement in the current decade. Since the previous decades a great attention has been given to the https://doi.org/10.1016/j.asr.2019.03.037 0273-1177/Ó 2019 COSPAR. Published by Elsevier Ltd. All rights reserved. ⇑ Corresponding author at: CONACYT, SCiESMEX, LANCE, Insti- tuto de Geofisica, Unidad Michoacan, Universidad Nacional Autonoma de Mexico, Antigua carretera a Patzcuaro 8701, Morelia, Michoacan C.P. 58089, Mexico. E-mail address: maria.a.sergeeva@gmail.com (M.A. Sergeeva). www.elsevier.com/locate/asr Available online at www.sciencedirect.com ScienceDirect Advances in Space Research xxx (2019) xxx–xxx Please cite this article as: D. V. Blagoveshchensky, M. A. Sergeeva and P. Corona-Romero, Features of the magnetic disturbance on September 7–8, 2017 by geophysical data, Advances in Space Research, https://doi.org/10.1016/j.asr.2019.03.037