Earth’s magnetosphere cracked by massive solar activity

The last month of May 2023, the Earth’s magnetosphere has been cracked. The Sun has had a rather “wild” behavior so stronger to attract the attention of researchers.

As it’s known, the Sun has a rotation period of about 25 days at the equator. They become 27 synodals at the equator if, in the latter case, we refer to the reappearance of a certain regions (such as sunspots or AR-Active Region) at the same point of the previous month observed from the Earth. This is because in its path around the Sun, our planet has “forced” the Sun to those two extra days, to make the spot reappear in the same optic position.

Since May 17, 2023, these regions have become notably active, resulting in the solar wind attaining an above-average speed of 429 km/s. At this rate, it takes approximately 58 minutes for the solar wind to travel from the NASA DSCOVR probe to Earth, which is positioned at orbit L1, approximately 1.6 million km away.

This last month the Sun has manifested a more active behavior than usual. From the beginning of the month until May 17, some 18 Class M flares were counted by the Spaceweather center. Some produced coronal mass ejections and others did not. A week earlier, on May 9, an M4.2 solar flare appeared from the sunspot region AR 3296.

This solar flare wasn’t the strongest M-class solar flare we’ve seen in recent days, but it’s interesting because it was highly eruptive.

The long-duration event was associated with type II and IV radio scans and launched a full-halo coronal mass asymmetric ejection, as seen in the animation at SOHO/LASCO probe.

Yesterday's M4.2 flare from sunspot region 3296 launched an asymmetrical full halo coronal mass ejection as seen here by SOHO/LASCO.

While most of the ejecta is heading to the north-west, we think it is very likely that this plasma cloud will arrive at Earth late on May 11. pic.twitter.com/Yo3FsPdUPG

— SpaceWeatherLive (@_SpaceWeather_) May 10, 2023

While most of the ejected material headed northwest, the plasma cloud reached Earth on May 11, developing a geomagnetic storm G2 after the arrival of the plasma cloud. The events that characterized the week from May 9 were warning signs of the May 16 event, when a solar flare was observed just over the horizon (to see animation, click here).

Well, this flare, although beyond the horizon, touched the Earth with a Class M9.6 force, a few decimals under an X-flare and there were quite important effects. The radiation ionized the top of our planet’s atmosphere, causing a deep shortwave radio blackout over North America.

The horizontal lines in this dynamic spectrum, are terrestrial radio stations. All of them faded sharply immediately after the glow. The signal loss lasted 10 minutes at the top of the band (27 MHz) and more than 20 minutes at the bottom (16 MHz). This is typical of solar radio blackouts: lower frequencies are hit hardest. And we arrive at May 20, when, two days after the appearance of the AR 3310 and AR 3311, the spaceweather alarm bells were activated.

A crack has opened in the Earth’s magnetic field while a region of negative BZ has poured onto our planet. If the Sun’s magnetic field points south — a condition scientists call “southward Bz” — then the Sun’s magnetic field can partially cancel out Earth’s magnetic field at the point of contact.

The geomagnetic storms of last May 19-20, of which we have spoken with a certain level of attention, produced a solar wind of about 500 km / s that caused a breach in the Earth’s magnetic field for several hours. The storm was, at the time of magnetosphere contact, a moderate Type G2, while the first X and M signals from the Active Regions AR 3310 and AR 3311 raged on the solar surface.

What happens in a crack or “geomagnetic fracture”?

Exactly what happens in planets without a magnetic field… It can generate strong electric fields in the atmosphere, favor the appearance of green or red flashes, create radio interference even on the ground and, most importantly, tear several hundred cubic kilometers of atmosphere into space.

Is it dangerous?

Yes, if the Earth’s magnetic field is not able, as Mars, to regenerate the wound and close the fracture. Fortunately, the Earth is still able to heal itself precisely because the magnetic field continues to operate while the solar wind, once the storm has ceased, ceases its violent action.

This time it went well and there were no further phenomena worthy of note but the possibility that a Carrington Event could be triggered was not so remote. We will continue to monitor the Sun in anticipation of further “tantrums” from the Sun as we head towards the peak of activity expected in 2025.