Session 24 January 2026

[Gaby]

Q: (Gaby) During the beginning of the resulting geomagnetic storm on January 19th, a couple of witnesses located at the epicenter of the South Atlantic Anomaly saw a strange purple band. The data shows that auroras are relatively weak in the anomaly, and this effect is more pronounced during high geomagnetic activity. What did they see and why?

A: Aurora and SPA.

Q: (L) Weaker geomagnetic field.

An update on the phenomena above. According to mainstream source (Space.com), it's another Cs hit. BTW, here's the picture of the strange purple band that we didn't attach to the session:

Astrophotographer Egon Filter captured the faint purple-red glow from Cambará do Sul, in Brazil's Rio Grande do Sul state, during the peak of the geomagnetic storm. Auroras are typically confined to high latitudes near Earth's north and south magnetic poles, making sightings in the Southern Hemisphere this far north of Antarctica very rare.

Filter had always dreamt of photographing the aurora australis (southern lights) in Brazil, but Rio Grande do Sul state is located between the 27 and 33 degrees south latitude, far outside the usual auroral zone.

"For an aurora to be visible at low latitudes, a very violent and exceptional solar storm is necessary," Filter told Space.com in an email.

And as noted, the X flare was not a particularly strong one, however, it did produce a powerful geomagnetic storm.

The short-lived display occurred inside the South Atlantic Anomaly [SAA], a region where Earth's magnetic field is weaker than elsewhere, according to spaceweather.com. This region is usually associated with suppressed auroral activity, not enhanced displays, and one leading explanation is that the weak and disorganized magnetic fields in the anomaly do a poor job of focusing and accelerating solar wind particles. As a result, any auroras that do form tend to appear as faint, diffuse glows rather than bright, well-defined curtains.

That makes sense.

Spaceweather.com noted that the glow could also potentially have been a stable auroral red (SAR) arc, a diffuse band that can appear during strong geomagnetic storms when energy from Earth's ring current leaks into the upper atmosphere. SAR arcs have been observed at lower latitudes during strong storms and are typically quite faint.

However, the Cs said it was an aurora, not a SAR arc.

However, solar physicist Tamitha Skov says the geometry of the Brazilian observation points more strongly to aurora than a SAR arc. "What makes this particular observation more remarkable is that it is observed high in the sky over Brazil and not near the southern horizon," Skov told Space.com. Given Brazil's low latitude, Skov explained that the glow was most likely diffuse equatorial aurora penetrating through the South Atlantic Anomaly, rather than a SAR arc, which is more commonly found hugging the horizon.

"It is aurora, but it is diffuse (not discrete) and it comes from a different source than we typically associate with the auroral zone," Skov explained.

While the sight is rare, Skov emphasized that it was not unexpected. She explained that the sun is currently returning to a more "active posture" and that recent solar activity is closer to what scientists consider normal when averaged over the past 24 solar cycles.

"These observations are consistent with the expected behavior from the Sun-Earth system, right now," Skov said. "Many of us have been predicting we would see this kind of aurora for years now. In fact, some of us have actively asked aurora field reporters to be on the lookout for it."

Very nice how they wrapped up such a unique and rare event as an expected behavior for a solar cycle that is "average as usual". It's pretzel-like reasoning. The last bit it's true: solar cycle is nothing spectacular compared to past ones from decades ago. Compared to the last solar cycle, it's definitely more active. But it's rare to see auroras in the SAA, as they say above: SAA is "associated with suppressed auroral activity, not enhanced displays, and one leading explanation is that the weak and disorganized magnetic fields in the anomaly do a poor job of focusing and accelerating solar wind particles."

So no, these observations are not consistent with expected behavior from the Sun-Earth system. Something is different, i.e. weaker geomagnetic field.