Sol (Sun) and its phenomena

[Olivierlejardinier]

Unexpected X flare earlier today, from spaceweather.com :

OUT OF NOWHERE, AN X-FLARE: The forecast called for quiet. Instead, the sun produced an X1.1-class solar flare on May 25th (0152 UTC). X marks the spot in this extreme ultraviolet image from NASA's Solar Dynamics Observatory:

The source of the explosion is new, fast-growing sunspot 4098. At the beginning of the weekend, this sunspot was almost invisibly small, but now it has a primary core larger than Earth with multiple Moon-sized cores trailing behind.​

Radiation from the flare ionized the top of Earth's atmosphere, causing a brief shortwave radio blackout over the Pacific Ocean. Ham radio operators may have noticed a loss of signal strength at all frequencies below 20 MHz around 0200 UTC.

We do not know if more flares are forthcoming. If the sunspot's growth continues apace, rapid changes in its magnetic field could lead to explosive reconnection.

According to the spaceweather's chat, there's not much to it in terms of earth directed CME, yet.

 

[mabar]

SUPER FAST SOLAR WIND (UPDATED): Solar wind is blowing around Earth faster than 750 km/s (1.7 million mph). This is putting pressure on our planet's magnetic field and setting the stage for possible G1/G2-class geomagnetic storms on May 30th. High-latitude sky watchers should remain alert for auroras. Aurora alerts: SMS Text

A 24-HOUR GEOMAGNETIC STORM: A co-rotating interaction region (CIR) hit Earth on May 29th, sparking 24 hours of non-stop geomagnetic storming. The day started off strong (G3) before settling into a sustained stretch of minor to moderate disturbances:​

Faster than 750 km/s, according to NASA, coronal holes produce solar wind of high speed, ranging from 500 to 800 kilometers per second. I suppose the sun will continue to surprising us and institutions will continue to modify parameters.

According to xras.ru (Telegram Channel)

The speed of the solar wind, by the way, has been growing to some truly inadequate levels in the last few hours. You don't see that often from plasma emissions after record X flares.

May 30, 2025, 09:48 Moscow time

Geomagnetic conditions as of the morning of May 30, 2025

There have been no significant changes compared to the previous day. The planet continues to be under strong pressure from a group of coronal holes, clearly visible to the "naked eye" on the side of the Sun facing the Earth . It was previously noted that with such a complex configuration of holes (a large number of objects located at different latitudes and longitudes), the final configuration of the disturbed region that has reached the Earth is almost impossible to calculate, and surprises are possible. At least in this sense (in terms of surprises), the "forecast" has been completely justified. Over the past 24 hours , exceptionally high and greatly exceeding expectations solar wind speeds have been recorded, sometimes reaching 850 km/s. The wind also has a high temperature and a noticeably increased magnetic field strength, that is, it has a whole set of features to complicate the life of any planet that carelessly gets in its way. At the moment, the Earth and, to some extent, the nearby Venus are suffering, which, in addition to everything else, does not have its own protective magnetic field.

Over the past 24 hours , a magnetic storm lasting more than 24 hours was registered , which began yesterday at 3 a.m. Moscow time and stopped (most likely, briefly) only today at about 5 a.m. The further situation, as before, is difficult to predict. The general situation in the outer space surrounding the Earth continues to remain tense with no signs of rapid improvement. Mathematical models predict new medium-level storms with Kp close to 6 today .

 

[Olivierlejardinier]

Strong M8 flare to begin June, an impact on earth is very likely, the sunspot is almost facing toward our planet :

A SIGNIFICANT SOLAR FLARE: Earth-orbiting satellites have just detected an M8.2-class solar flare from big sunspot 4100. Although the flare is not technically X-class, it's close. Moreover, it was a slow explosion with lots of power "under the curve." Stay tuned for updates about this potentially significant Earth-directed event.

From spaceweather's chat, Coronagraph shows the CME :




Looks like the cme has been modeled in at least one model, but won't be surprised if it changes:

 

[Puma]

Strong M8 flare to begin June, an impact on earth is very likely, the sunspot is almost facing toward our planet :

Let the games begin

https://twitter.com/x/status/1928659528758997115

 

[Ruth]

Holy Smoke! Are we about to get 'zapped'? Big time?

 

[Ellipse]

Looks like the cme has been modeled in at least one model, but won't be surprised if it changes

Yeah it's a forecast. I extracted picture for the prediction at 6:00 am this morning. I guess it's UTC time. We can see the "small wave".



It's actually 9:30 UTC and I wonder if we have in real time the data of the CME and if it's really coming. There's so much data all over there. If someone know a link. Last pictures from the Stereo satellite (9:05 am), I don't know if we can decipher something from this:



Source:

STEREO - Science Center - Latest Images

 

[Ellipse]

The NOAA have just updated their forecast (30 minutes ago):

:Product: Forecast Discussion
:Issued: 2025 May 31 1535 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
Solar Activity

.24 hr Summary...
Solar activity reached high levels due to frequent M-flare activity.
Region 4100 (N08E07, Eki/beta-gamma-delta) produced a long-duration M8.1
(R2-Moderate) flare at 31/0005 UTC, the strongest of the period. Type II
(estimated shock: 1,938 km/s) and Type IV radio sweeps as well as a
Tenflare (1,100 sfu) and a Castilli-U radio signature were also
observed. Wide-spread coronal activity in EUV imagery was followed by a
full-halo CME signature, first identified in GOES-19 CCOR-1 imagery at
31/0030 UTC. The event is current still being analyzed and modelled to
determine the CMEs estimated time of arrival at Earth.

The M3.4/1b flare at 30/0613 UTC, produced by Region 4100 was analyzed
and modelled. WSA-Enlil results suggested Earth is likely to see the
periphery of the CME on 03 Jun.

Other activity included an impulsive M4.5/1n (R1-Minor) at 31/0808 UTC.
A Tenflare (220 sfu) and Type IV radio sweep accompanied the event. No
potentially Earth-directed ejecta was observed in subsequent coronagraph
imagery.

.Forecast...
Solar activity is likely to be moderate with elevated potential for
M-class flares(R1/R2 - Minor/Moderate) and a slight chance for an
X-class flare (R3 - Strong) over 31 May- 02 Jun.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux reached high levels, with a peak of
4,876 pfu at 30/1700 UTC. The greater than 10 MeV proton flux remained
below S1 (Minor) threshold despite a slow-rising trend that followed the
M8.1 flare from Region 4100.

.Forecast...
The greater than 2 MeV electron flux is expected to be at moderate to
high levels on 31 May - 02 Jun May due to coronal hole influence. There
is an increasing chance for an S1 (Minor) solar radiation storm on 31
May - 02 Jun due to recent activity from Region 4100 as well as
potential for future energetic eruptions.

Solar Wind

.24 hr Summary...
Solar wind parameters reflected a negative polarity CH HSS regime. Solar
wind speeds were between ~650-800 km/s, total magnetic field strength
ranged from 4-7 nT, and the Bz component reached a maximum southward
deflection of -7 nT. Phi angle was predominantly negative.

.Forecast...
Enhanced solar wind conditions are expected to continue through 02 Jun
as coronal hole HSS activity persists.

Geospace

.24 hr Summary...
The geomagnetic field was at mostly active levels, with an isolated G1
(Minor) period at the beginning of the UT day. All elevated geomagnetic
conditions were due to the influence of a large, trans-equatorial,
negative polarity, polar-connected coronal hole.

.Forecast...
Active to G1 (Minor) storm conditions are likely early on 01 Jun as CH
HSS conditions persist. By as early as late on 01 Jun to early on 02
Jun, conditions are expected to increase rapidly with the arrival of the
expected CME from 31 May. G3-G4 (Strong-Severe) conditions are likely,
with a chance for G5 (Extreme) levels on 01-02 Jun.

****AMD for increased geomagnetic activity forecast****

Source:

Forecast Discussion | NOAA / NWS Space Weather Prediction Center

www.swpc.noaa.gov

According to @Olivierlejardinier the hit is around midnight UTC:



The peak at 15:00 UTC from the NOAA:

 

[mabar]

Xras.ru Update it as well

The results of the calculation of the movement of the plasma ejection from the Sun to the Earth have arrived. Arrival is tomorrow at 16:00 Moscow time.

The most probable calculated scenario of the movement of the night plasma ejection after the M8.2 flare from the Sun to the Earth has been selected. The modeling was performed based on the ENLIL hydrodynamic code using the WSA and CONE models (calculated by NOAA). According to the results, the ejection has a pronounced double structure: two clouds following each other and, at the level of the Earth's orbit, merging into one. The second front is formed by the substance of a large prominence ejected synchronously with the flare, which was mentioned earlier today .

Calculations confirm the exceptionally high speed of the plasma, about 1200 kilometers per second. It will take the plasma only about 37 hours to cover the distance of 150 million km separating the Earth and the Sun. The preliminary arrival of the gas cloud to the Earth is expected tomorrow at about 16:00 Moscow time . The video uses the universal time scale UTC, which is 3 hours behind Moscow time, where this moment is 13 UTC.

About 20-30 minutes before reaching Earth, the plasma should hit a constellation of spacecraft located at the L1 Lagrange point 1.5 million km closer to the Sun, including the SoHO spacecraft, on which the LASCO telescopes are based. Information from these satellites will be a certain warning for the entire constellation of spacecraft based near Earth.

Link to uncompressed video (9 MB, GIF):

https://xras.ru/info/images/20250531_enlil.gif

EXPLANATION: The left frame shows a top view of the plane of the planets. The Earth is the green dot on the right side of the picture. Above, the red dot shows the position of the STEREO-A spacecraft, observing the Sun from the side. The right frame shows a side view of the Earth (north is at the top, south is at the bottom). The Sun is shown as a yellow circle in both pictures.

---
IMPORTANT: the first NOAA forecast for the Kp index has been posted

The first forecast for the geomagnetic index Kp from NOAA has been generated. The forecast is not yet fully consistent with the ENLIL calculation results published above and was issued based on a different branch of the scenario tree, corresponding to a lower average ejection velocity of 950 km/s. The plasma arrival has been shifted accordingly by 8 hours, to midnight, and the peak Kp index has been reduced from 8.0 to 7.7. The forecast will be updated.

 

[Ellipse]

For information, the Kp index (p is for planetary) is one of the most commonly used indices to indicate the severity of global magnetic disturbances in near-Earth space.

The Kp-index is the global geomagnetic activity index that is based on 3-hour measurements from ground-based magnetometers around the world. Each station is calibrated according to its latitude and reports a certain K-indice depending on the geomagnetic activity measured at the location of the magnetometer. The K-index itself is a three hour long quasi-logarithmic local index of the geomagnetic activity at the given location and time compared to a calm day curve. A magnetometer measures the maximum deviation of the horizontal component of the magnetic field at its location and reports this. The global Kp-index is then determined with an algorithm that puts the reported K-values of every station together. The Kp-index ranges from 0 to 9 where a value of 0 means that there is very little geomagnetic activity and a value of 9 means extreme geomagnetic storming.

source : The Kp-index | Help

And the Wikipedia record:

K-index - Wikipedia

en.wikipedia.org

 

[Ellipse]

I don't know if they are on something for forecasting eruptions, I post it for the record. In another post they allude to the Fibonacci sequence.

We nailed it! Predicted an M5.0–M8.0 flare for late May back in April, and the M8.2 flare hit on May 31, 2025, at 00:05 UTC from AR4100, after an M3.4 flare on May 30. G3–G4 storm coming June 1! Our harmonic 377 Hz method works Now refining for Sep 10–11: M5.5–M7.5 flare, G3–G4 storm, 135–165 sunspots. If we hit this, it’ll be remarkable!

https://twitter.com/x/status/1928900571311804748

 

[Ellipse]

We can already see indicators raising:











Source:

ACE Real-Time Solar Wind | NOAA / NWS Space Weather Prediction Center

www.swpc.noaa.gov

 

[Ellipse]

To be clear, the data are from the ACE (Advanced Composition Explorer) satellite. The satellite is at the Lagrange 1 point.

The solar storm is hitting the satellite:


Source

and begin to hit Earth. Photo from New Zealand:

 

[Kadam303]

 

[XPan]

Wow !

It really has reached extremly strong levels... 180 GW !

 

[mabar]

From xras-ru wow! very interesting times and ahead!

01 June 2025, 09:43 Moscow time

EXTREMELY IMPORTANT: A mass ejection with record characteristics in history reached Earth almost a day earlier than predicted

Absolutely unexpected and so far simply inexplicable events are now happening near the Earth.

According to the readings of several space tracking devices (at least ACE and DSCOVR), a cloud of plasma ejected by the Sun yesterday has arrived at Earth.

An exceptionally strong jump in all parameters of the interplanetary environment was recorded today at 08:30 Moscow time. The speed of the solar wind now sometimes exceeds 1000 km/s. Very high values of density and temperature are
also observed. The latter, according to satellite readings, is now more than 2 million degrees with normal values of about 100 thousand degrees, i.e. it has higher values than the plasma temperature in the Sun's corona. There is a possibility that such values have never been recorded in the history of observations, or are close to historical maximums.

If we are talking about the plasma cloud ejected yesterday reaching the Earth, and it is difficult to come up with other explanations, then it covered the distance from the Sun to the Earth in an exceptionally fast, close to record, time, less than 30 hours, almost a day faster than the forecast.

At present it is difficult even to understand what is happening, so much the incoming data contradicts the forecasts and expectations. There is hope that a small, exceptionally fast plasma fiber has arrived to the Earth, possessing, for unknown reasons, a rare speed and other parameters, and the main mass of gas has more moderate characteristics and will arrive later.

If we are talking about the main emission, then today it is almost inevitable that storms of the 5th highest level will begin in the very near future.

PS: solar wind parameters now: Солнечный ветер актуальные данные

----

Temperature values of 3.5 MILLION DEGREES have been reached.

I just don't know how to comment on this.

---

AT THE CURRENT MOMENT - IN BRIEF

The Earth continues to be in what is identified (correctly or not, is not entirely clear) with yesterday's mass ejection. Over the past three hours, the solar wind speed , measured outside the Earth's magnetosphere, has been at a level of over 1000 km/s, sometimes rising to 1100 km/s and going beyond the graphs on the site. At the same time, very high temperatures are measured in the plasma flow approaching the Earth (at times, completely unrealistic values are received). A very high magnetic field induction is also recorded, accompanied by constant changes in the direction of the field.

The main mystery is the low plasma density, which is not only insufficient for such a large emission, but simply shows values lower than in the usual undisturbed solar wind. The general impression is that the Earth was hit by a very wide, fast, but almost empty tube of twisted magnetic field. The low density partially explains the high temperature values, since with a small number of particles the very concept of temperature loses its meaning, and the chaotic (real thermal) component of the velocity is isolated with very large errors.

The planetary index Kp is currently at the level of G4 . Although yesterday such indicators would have looked exceptionally high, now it is clear that we are talking about playing for completely different stakes, and the question is whether the geomagnetic index will reach level 5 in the coming hours. Also, the question still remains open as to what is happening, and what specific structure has come to the planet now, and, more importantly, whether this is already the main body of the ejecta, or the main dense core is still on its way.

Science at the moment is, in general, in the same passive observer mode as everyone else.

UPDATE: as of 14:00 Moscow time

At the moment, there are no convincing signs of a decrease in temperature and solar wind speed. A small decrease in the Kp index value (now about G3 versus G4 two hours ago - shown in the graph above) is ephemeral and is only due to the fact that the interplanetary magnetic field is temporarily turned in the north direction, in which it suppresses the development of magnetic storms. As soon as it turns back, even briefly, the index will jump to the G4 level again and resume attempts to break through the G5 threshold.

As already noted, in the next couple of hours, if we believe the initial calculations, the main mass of the ejection should arrive or not arrive, since for now the Earth is hit by almost “empty” magnetic field tubes, and where all that mass
that flew away from the Sun yesterday is located is completely unclear.

The main chart in this regard for the next few hours will be the density chart. The dense core that has arrived should give a jump first of all on it: https://xras.ru/image/swn_RAL5_20250601.png