An ionospheric response at middle latitudes to geomagnetic storms is not yet very well understood. Total electron content (TEC) variations associated with eight strong geomagnetic storms between 2015 and 2022 obtained from GNSS receivers in the western area of the North Atlantic (Portuguese continental and insular territory) are studied in an attempt to fill this gap. It was found that for most of the studied geomagnetic storms TEC variations are synchronous for the longitudinal ranges from 27ºW and 9ºW. In the southern part of the studied region (around 32ºN) the amplitude of TEC variations is, in general, significantly higher than in the northern part (around 39ºN). Some of the studied geomagnetic storms were associated with TEC variations that we interpret as effects of post-sunset equatorial plasma bubbles that travelled well north from their habitual region. Also, while most of the studied storms were accompanied by reports on different kind of malfunction of GNSS systems (GPS; GALILEO and other), there is no clear pattern in their appearance in dependence on the geomagnetic/ionospheric storms’ strength, commencement time, and its characteristics, in general.

The microstructure evolution and grain refinement kinetics of a solution treated Cu – 0.1Cr – 0.06Zr alloy during equal channel angular pressing (ECAP) at a temperature of 673 K via route B_C were investigated. The microstructure change during plastic deformation was accompanied by the microband formation and an increase in the misorienations of strain-induced subboundaries. The refinement of initial coarse grains was considered as a result of continuous dynamic recrystallization. The dynamic recrystallization kinetics was discussed in terms of grain/subgrain boundary triple junction evolution. The strain dependence of the triple junctions of high-angle boundaries can be expressed by a modified Johnson-Mehl-Avrami-Kolmogorov relationship with a strain exponent of about 1.49. Severe plastic deformation by ECAP led to substantial strengthening of the Cu-0.1Cr-0.06Zr alloy. The yield strength increased from 60 MPa in the initial state to 445 MPa after the total strain of 12.