Sol (Sun) and its phenomena

[Puma]

Does "geomagnetic field being at quiet levels" mean the same as you saying "e-m field being active"?

No. The SpaceWeather report I posted on October 10 was the latest update on the site for October 9 at 22:00 UTC. At that time, the geomagnetic field was quiet. However, this was not the case during the early hours of the same day. SpaceWeatherlive reported active geomagnetic conditions at 02:59 UTC.


Scale: The Kp index ranges from 0 to 9, where:

0: Very quiet geomagnetic conditions.
1-3: Low to moderate geomagnetic activity.
4-5: Active geomagnetic activity or minor geomagnetic storms.
6-7: Moderate to strong geomagnetic storms.
8-9: Severe or extreme geomagnetic storms.

There are reports that consider kp 0-3 to be quiet or normal. The most significant activity actually occurs from Kp 4 (active) onwards.

Now, I understand the confusion. The SpaceWeatherlive report should say

"The geomagnetic field has been at active to quiet levels for the past 24 hours."

I don't understand why, but the site administrators choose the last status or when the field changes from quiet to active, from active to unsettled or unsettled to severe. They do not report from a higher-level event to a lower-level one (active to quiet). On several occasions, I faced the decision to change the status of the forum report to avoid this confusion.
​

If anything, the comparison between the two suggests that more dominant factor in creating significant geomagnetic disturbances and storms would more likely be the IMF, which intensity was higher back then reaching even 20 nT on September 30th, than solar wind speed.
The solar wind density might play a role too though, through dragging the solar magnetic field lines maybe, and perhaps also the configuration of the so called heliospheric current sheet at the time.

So it seems it's not only, "there's a CH on the solar disc, the solar wind coming from it is going to make 'chaos' here on Earth," but there seem to be other things possibly more important, like magnetic conditions in the heliosphere for example, that could determine the exact outcome of each particular case on individual basis.

Yes, you are correct. There are many other factors to consider. The consequences of a strong IMF and high velocity are more evident in phenomena on Earth when they combine, and there may be other factors such as the gravitational force of the planets.

This was the report for September 30​

The geomagnetic field has been at unsettled to severe storm levels for the past 24 hours. Solar wind speed reached a peak of 744 km/s at 30/1921Z. Total IMF reached 20 nT at 30/1139Z. The maximum southward component of Bz reached -17 nT at 30/0453Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 413 pfu. SpaceWeatherlive​

On October 30 coincidentally, two ≥M6.0 earthquakes were recorded. After the value of 20 nT and before the wind reached a speed of 744 km/s, this speed is obviously not sudden but increases from an average value of approximately 400 km/s.​

M 6.9 - 11 km ESE of Calape, Philippines
2025-09-30 13:59:43 (UTC)
11.151°N 124.138°E. 10.0 km depth
USGS earthquake alert

M 6.0 - 32 km SE of Kalianget, Indonesia
2025-09-30 16:49:42 (UTC)
7.240°S 114.170°E. 13.9 km depth
USGS earthquake alert

There is undoubtedly much to observe and learn.

 

[Pat]

No. The SpaceWeather report I posted on October 10 was the latest update on the site for October 9 at 22:00 UTC. At that time, the geomagnetic field was quiet. However, this was not the case during the early hours of the same day. SpaceWeatherlive reported active geomagnetic conditions at 02:59 UTC.
View attachment 112724

Scale: The Kp index ranges from 0 to 9, where:

0: Very quiet geomagnetic conditions.
1-3: Low to moderate geomagnetic activity.
4-5: Active geomagnetic activity or minor geomagnetic storms.
6-7: Moderate to strong geomagnetic storms.
8-9: Severe or extreme geomagnetic storms.

There are reports that consider kp 0-3 to be quiet or normal. The most significant activity actually occurs from Kp 4 (active) onwards.

Now, I understand the confusion. The SpaceWeatherlive report should say

"The geomagnetic field has been at active to quiet levels for the past 24 hours."

I don't understand why, but the site administrators choose the last status or when the field changes from quiet to active, from active to unsettled or unsettled to severe. They do not report from a higher-level event to a lower-level one (active to quiet). On several occasions, I faced the decision to change the status of the forum report to avoid this confusion.



Yes, you are correct. There are many other factors to consider. The consequences of a strong IMF and high velocity are more evident in phenomena on Earth when they combine, and there may be other factors such as the gravitational force of the planets.

This was the report for September 30


On October 30 coincidentally, two ≥M6.0 earthquakes were recorded. After the value of 20 nT and before the wind reached a speed of 744 km/s, this speed is obviously not sudden but increases from an average value of approximately 400 km/s.​

There is undoubtedly much to observe and learn.

Do you mean 30th September rather than 30th October?

 

[Olivierlejardinier]

Flaring activity on the sun increased in the last 24 hours, peaking for now at M1.9 from sunspot AR4246.



A comment from spaceweatherlive says there a chance of earth-directed ejection; and here's what the Russian institute posted regarding the new sunspots group:

In general, active regions have started to grow on the Sun. The spots themselves are harmless structures, but if they appear out of nowhere on a blank area, it is only in response to an eruption of strong magnetic fields with large energy reserves from the depths to the surface. The faster the corona is pumped with energy, the faster the spots grow.

Flares will resume by evening.(this was yesterday) The star will start burning energy.

It's all quite intense, actually. This really makes you believe in the second peak of activity.

Same source this morning:

Strong solar flares have resumed on the Sun despite forecasts

It's hard to add anything to the headline. This is how it looks through telescopes. And this is how it looks on the chart. Two fires currently burning in the center of the solar disk are two active centers about 150 thousand km each in size (more than 10 Earth diameters), where the Sun is burning energy released yesterday from the star's depths (generation occurs about 200 thousand km below the surface) and still continues to arrive. Each burst is a flare of level C or M (no higher X-class flares yet).

The break in activity, as seen on the same chart, occurred yesterday around 4 p.m. Moscow time against the backdrop of exceptionally optimistic images drawn by models. Honestly, it’s unclear where all this came from. The star had a rather turbulent end of September and beginning of October, and it shouldn’t have recovered so quickly.

The current flare level is now at M1.0 — M2.0. The four-month maximum is M6.4 (the flare was on September 28). It might be surpassed. To set records for a period longer than 4 months, it will be necessary to reach X-class flare levels. Purely by eye, the potential for this is not yet visible, although you can’t really judge by eye.

In general, on the Sun, whether you like it or not, there is a full systemic flare, and all that remains is to monitor it. Yes, the geomagnetic indices response will start around Wednesday, maybe Thursday.

 

[Puma]

Do you mean 30th September rather than 30th October?

Yes, Thank you.

It should be

On SEPTEMBER 30 coincidentally, two ≥M6.0 earthquakes were recorded. After the value of 20 nT and before the wind reached a speed of 744 km/s, this speed is obviously not sudden but increases from an average value of approximately 400 km/s.