Solar alert

Issued on 2021 Apr 25 0939 UTC

The in situ observations show arrival of the shock wave at about 22:26 UT on April 24. The sudden increase of the interplanetary magnetic field strength (from 5 to 10 nT), was simultaneous with the density, solar wind velocity and temperature increase. The shock wave was driven by the partial halo CME first seen in the SOHO LASCO C2 field of view at about 06:12 UT on April 22. The CME was associated with C3.8 flare (peaked at 04:35 UT) that originated from the Catania sunspot group 87 (NOAA AR 2816) at that moment situated at the center of the solar disc. Arrival of the shock wave induced disturbed geomagnetic conditions (Kp=5 and K=5, reported by Dourbes and NOAA respectively).

Reference for this alert

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