Traveling ionospheric disturbances over midlatitude Europe during CIR/HSS driven magnetic storm on March 30 – April 6, 2023

Understanding the generation, propagation and attenuation of traveling ionospheric disturbances (TIDs) during strong space weather variations is essential for predicting and mitigating the adverse effects of TIDs on communication, navigation, and other technological systems that rely on the ionosphere. The magnetic storms caused by coronal mass ejections (CME) and corotating interaction regions / high-speed stream (CIR / HSS) are drivers which can affect the ring current and also the course and duration of auroral activity in different ways. Moreover, despite the greater energy output of CME-driven storms, the magnetospheric coupling and total energy input are often more geoeffective for the magnetic storms driven by CIR / HSS events. The objective of the current case study is to investigate thoroughly the TIDs over midlatitude Europe, originated by the CIR / HSS - driven storm on March 30 – April 6, 2023. We employed the data from European dense GNSS receiver network and four ionosondes for joint analysis to detect both large-scale and medium-scale TIDs and estimate their characteristics. We detected several time intervals with intensification of both types of TIDs propagating from the high latitudes towards the equator and associated with an increase in auroral activity. Ionosonde and GNSS based results show the consistency in estimation of characteristics of TIDs, which have the dominant periods of 30 – 80 min, horizontal phase velocities of 200 – 600 m/s and horizontal wavelengths of 400 – 3500 km. We also compared TID occurrence and direction during the comparable magnetically quiet and CIR / HSS - driven storm periods. We noted the significant increase in TID occurrence rate and the prevalence in their southward propagation during the observed magnetic storm. Based on this case study, we spotted that the TIDs at midlatitudes were usually observed several (1 – 4) hours after the increase in the auroral activity characterized by IMAGE IE indices. We continue to analyze other CIR / HSS driven events to establish the validity of such a relationship.