The strongest part of the geomagnetic storm that started on June 1st subsided by the morning of June 2nd, though further bursts, possibly strong ones, are still expected. According to the Solar Astronomy Laboratory of the IKI RAN and ISZF SB RAS, the likelihood of a higher, fifth level storm is not expected.
Preliminary analysis indicates that the mass ejection observed yesterday exceeded those responsible for the largest magnetic storms in 20 years, specifically the one on May 11, 2024, in both speed (1100 km/s compared to 1000 km/s) and temperature (2-3 million degrees compared to 1 million degrees). However, it was weaker in terms of peak magnetic field values (25 nT vs. 50-70 nT) and the density of the incoming plasma (1-2 protons per cubic cm vs. 10-20 a year ago).
Astronomers highlight the low density of yesterday’s incoming cloud as a significant mystery. The total mass of solar matter reaching Earth seems inconsistent with the volumes ejected by the Sun, as recorded by coronagraphs.
Peak values of the magnetic storm occurred around noon on June 1st, when the geomagnetic index Kp reached level G4. Around this time, magnetic fluctuations were sharply suppressed by the positive component of the interplanetary magnetic field, which inhibits processes that create magnetic storms. This contrasts with the May 11 event of last year, where a strong negative component dominated, significantly weakening the magnetosphere’s protective capabilities.
The positive component suppressed the storm’s development and stabilized the situation to moderate disturbance levels throughout the second half of the day.
As of the morning of June 2nd, the situation near Earth remains highly disturbed. Solar wind speed and temperature, while not at record levels, remain very high. The “blocking” effect of the positive field direction has ceased, and auroras are appearing over North America. There is a possibility of a delayed arrival of a dense core of the ejection. Full stabilization of the geomagnetic situation is not anticipated until June 4th.