Quiet before the storm – over!

Last week (starting with June 18) the Sun has launched consecutive solar storms and M-class flares. The shock front of first storm (originating from active region 2371) hit Earth yesterday, around 16.40 UT, with sudden jumps in all measured solar wind properties (Figure 1).

Solar wind parameters of IMF, speed, and density at L1, provided by ACE.
Solar wind parameters of IMF, speed, and density at L1, provided by ACE.

This sudden impulse caused a sudden but moderate enhancement in the GIC proxy dB/dt measured at Tromsø. Note that the field remains disturbed, which disturbances (especially around 21 and 06 UT) can be easily traced back to respective massive solar wind fluctuations depicted above.

Tromsø dB/dt
Rate of change of geomagnetic components (dB/dt) at Tromsø

The global effect is clear from the following plot: at the same time considerable GIC with ~3 A was modelled, using observed dB/dt values, in the natural gas pipeline situated at Mäntsälä, Finland, by the Finnish Meteorological Institute (FMI).

GIC at Mänstälä pipeline /source: FMI/
GIC in Mänstälä pipeline
/source: FMI/

Accordingly, the consecutively arriving solar storms in the upcoming few days may cause power grid fluctuations, and our high-latitude region is especially vulnerable. Also, loss of GPS lock, issues for amateur radio and GNSS operators may be observed.