Intensive Substorms during the Main Phase of the Magnetic Storm on March 23–24, 2023.

Here we studied the planetary features of the spatiotemporal distribution of ionospheric electrojets recorded in the onset of a substorm and in time on the activity maximum of three very intense substorms (with an AL-index from –1200 to –1700 nT) observed during the main phase of the strong magnetic storm on March 23−24, 2023. We have analyzed the substorms by applying the global maps of the planetary distribution of high-latitude ionospheric currents, compiled from simultaneous magnetic measurements on 66 low-orbit satellites of the AMPERE project, as well as ground-based magnetograms from the Scandinavian IMAGE profile and mid-latitude IZMIRAN stations located in the same longitudinal region. It was established that the onset of all the studied substorms on the IMAGE meridian was accompanied by the development of a nighttime current vortex with clockwise rotation, which is an indicator of an increase in downward field-aligned currents. The ground-based mid-latitude observations at the IZMIRAN station network confirmed that the center of the current wedge of the substorm was located in the nighttime sector significantly east of the IMAGE meridian. In the time of the substorm intensity maximum, a similar but more extensive current vortex was observed in the morning sector, which is probably typical of intense substorms. [ABSTRACT FROM AUTHOR]