Magnetic storm: infrastructure passes endurance test

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An extremely violent geomagnetic storm occurred at the weekend. Northern lights could be seen throughout Germany, and the observatory on Puerto Rico in the Caribbean reported the first northern lights sighting since 1921. Before that, the last time there were northern lights on Puerto Rico was in 1859 during the Carrington event, the mother of all geomagnetic storms. So this storm belongs in the series of really big events.

This comes as no surprise. The sun is currently at the peak of its eleven-year cycle. Over the last two weeks, a very large and magnetically complex group of spots has formed on the sun, producing increasingly violent X-ray bursts. The stronger such outbursts become, the higher the risk of a CME (coronal mass ejection). Just at the moment when the sunspot was in a favorable position to hit the Earth, a whole series of severe eruptions with powerful coronal mass ejections occurred.

Space weather is observed

The US weather agency NOAA is monitoring space weather very closely, as severe eruptions can affect satellites, power grids, navigation systems and radio transmissions. After analyzing satellite images, the NOAA issued a warning of a severe storm, category 4 out of 5. This last happened over 20 years ago and was an early indication that the storm could be particularly severe this time. But it got even worse: when the mass clouds reached the earth, the value for the magnetic disturbance reached category 5 in several three-hour periods.

Violent eruptions sometimes also cause a radiation storm. The sun then ejects large quantities of protons, which hit the high atmosphere with an energy of 10 MeV or more. This leads to a total blackout of short-wave communication in polar latitudes, which hardly anyone notices due to the small number of users. Satellites are worse affected: Their electronics can be disrupted and the solar panels can even be permanently damaged. Image sensors temporarily blinded by protons or tilting bits in storage units can even lead to the loss of satellites. The number of protons also increased during this event, but only very slightly. This may have prevented greater damage, as a magnetic storm reduces the protection of satellites from a radiation storm caused by the Earth's magnetic field, which deflects some of the charged particles.

Starlink under pressure

However, Starlink's satellite system came under pressure. The additional energy from the sun causes the ionosphere to heat up and expand. This slows down low-flying satellites (LEO, Low Earth Orbit) and forces them to compensate for the loss of speed with their engines so that they do not drop to a lower orbital altitude, where they are slowed down even more. Even if the satellite system functions normally again after this event, the service life of the satellites may have been shortened if a lot of fuel was used for unplanned orbit corrections. The connection to the Starlink satellites, whose poor quality many users complained about, was probably disrupted during the storm by the extremely active ionosphere, which diffracts and attenuates radio signals.

The higher-flying GPS satellites are not slowed down by the high atmosphere, but the system still loses accuracy during severe storms. This is because the signals have to pass through the highly excited ionosphere during a magnetic or radiation storm and are attenuated or deflected in the process. In the Midwest of the USA, farmers were unable to sow their crops because the GPS interference could no longer be compensated for, even with differential GPS (DGPS), and their tractors would have been thrown off course. However, car navigation devices were not affected by the inaccuracies; only applications that require maximum GPS accuracy were affected.

Another potential problem is power grids that extend over thousands of kilometers. Rapid and violent fluctuations in the earth's magnetic field can induce large currents in these systems, which can overload the transformers at the ends of the lines. If they are switched off to protect them, this can lead to power outages. Apparently, the precautions taken by operators worldwide have been successful, as there have been no reports of major power outages to date. The last regional blackouts were in Sweden and South Africa in 2003, and in 1989, 6 million people in the Canadian province of Quebec were left in the dark.

Endurance test passed

Apparently, power grids and satellites have withstood the endurance test well. However, this does not mean that there is no danger from the sun. A millennium event, i.e. a perfect storm in which several coronal mass eruptions unite, hit the earth exactly and are accompanied by a violent radiation storm, could cause massive damage. But the probability of this happening is extremely low. The infrastructure has already survived the storm of the century at the weekend.

(uma)