Sol (Sun) and its phenomena


The Living Force
FOTCM Member
Was going to post it at the norway spiral lights, by association of the word, but I think it is better here.

I was reading today at spaceweather this: said:
HELIOSPHERIC CURRENT SHEET: Today, April 7th, Earth is expected to cross through a fold in the heliospheric current sheet. The crossing could trigger unsettled conditions in our planet's magnetic field. NOAA forecasters estimate a 50% chance of minor geomagnetic storms. Aurora alerts: text or voice
The heliospheric current sheet separates regions of the solar wind where the magnetic field points toward or away from the Sun. The complex field structure in the photosphere simplifies with increasing height in the corona until a single line separates the two polarities at about 2.5 solar radii. That line is drawn out by the radially accelerating solar wind to form a surface similar to the one shown in this idealized picture. The surface is curved because the underlying magnetic pattern rotates every 27 days with the Sun.
It would take about 3 weeks for material near the current sheet traveling at 400 km/s in the solar wind to reach the orbit of Jupiter, as depicted here. In reality the surface becomes increasingly distorted because of variations in the solar wind speed along the surface and other dynamic effects operating in the interplanetary medium.

The shape of the current sheet usually evolves slowly - over months - as the large-scale pattern of the Sun's field changes in response to the emergence and decay of solar active regions. Coronal mass ejections often disrupt the background pattern temporarily, but sometimes the changes are permanent.

During most of the solar cycle the source of the heliospheric current sheet resembles a slightly tilted dipole with varying degrees of quadrupole distortion. Near solar maximum the polar dipole decays, leaving a much more complicated structure. This picture shows the heliospheric current sheet as it might appear during the rising phase of the cycle, when the dipole and quadrupole components are balanced; at this point the neutral line at the base of the sheet resembles the seam on a baseball. said:
Heliospheric current sheet

Heliospheric current sheet, the largest structure in the heliosphere.
The Heliospheric current sheet (HCS) is the surface within the Solar System where the polarity of the Sun's magnetic field changes from north to south[/b]. This field extends from the Sun's equatorial plane throughout the entire Solar System and is the largest structure in the heliosphere.[1] The shape of the current sheet results from the influence of the Sun's rotating magnetic field on the plasma in the interplanetary medium (Solar Wind).[2] (see also Unipolar generator). A small electrical current flows within the sheet, about 10-10 amps/m2. The thickness of the current sheet is about 10,000km.

The underlying magnetic field is called the interplanetary magnetic field, which has an associated interplanetary electric field [3], and the resulting electric current forms part of the heliospheric current circuit.[4] The Heliospheric current sheet is also sometimes called the Interplanetary Current Sheet and Heliospheric neutral sheet.

Ballerina's skirt shape
As the Sun rotates, its magnetic field twists into a Parker spiral,[5] a form of an Archimedean spiral, named after its discovery by Eugene Parker. As the spiraling magnetic sheets changes polarity, it warps into a wavy spiral shape that has been likened to a ballerina's skirt.[6][7] Further dynamics have suggested that "The Sun with the heliosheet is like a bashful ballerina who is repeatedly trying to push her excessively high flaring skirt downward"

Magnetic field
The heliospheric current sheet rotates along with the Sun once every 27 days, during which time the peaks and troughs of the skirt pass through the Earth's magnetosphere, interacting with it. Near the surface of the Sun, the magnetic field produced by the radial electric current in the sheet is of the order of 5x10-6T.[4]

The magnetic field at the surface of the Sun is about 10-4 tesla. If the form of the field were a magnetic dipole, the strength would decrease with the cube of the distance, resulting in about 10-11 tesla at the Earth's orbit. The heliospheric current sheet results in higher order multipole components so that the actual magnetic field at the Earth due to the Sun is 100 times greater.

Electric current

The electric current in the heliospheric current sheet has a radially component, the circuit being closed by currents aligned with the Sun's magnetic field in the solar polar regions. The total current in the circuit is on the order of 3×109 amperes.[4] As a comparison with other astrophysical electric currents, the Birkeland currents that supply the Earth's aurora are about a thousand times weaker at a million amperes. The maximum current density in the sheet is on the order of 10-10 A/m2 (10-4 amps/km2).

It has been noted that:
"It is remarkable that the radial component of the spiral structure implies a current the continually flows towards the Sun. The charge accumulating from this process must be removed elsewhere. This occurs most simply via line currents that originate over the Sun's poles"[9]

Interplanetary electric field
The interplanetary electric field (IEF) extends throughout the interplanetary current sheet, and is generally orientated north-south. The separation of the field is relatively small, but its extent is the same as the heliospheric current sheet which extends throughout the plasmasphere.

The interplanetary electric field is caused by ions leaving the Sun, initially flowing along and parallel to the Sun's magnetic field. But as the ions move further outwards, the azimuthal component of the Sun's magnetic field becomes more influential, and protons are deflected to the south and electrons to the north, resulting in an electric field that compensates the magnetic forces.[10]

Solar wind
"The Solar Wind consists of a hot plasma -- an electrically neutral mixture of electrons and ions (principally protons with some heavier atomic nuclei) at roughly 100,000°K. Its source is the Sun's atmosphere, or corona, and it is continually present in interplanetary space. The gas flows radially outwards at a typical speed of 450km per second to at least 70 AU and probably much further. The average speed of the flowing gas is remarkably independent of its distance from the Sun".[11]

Solar wind acceleration
"The speed of the solar wind away from Sun increases as the distance from the Sun increases. The wind accelerates rapidly in the first few tens of Ro, and accelerates only slowly after this."[12]

The heliospheric current sheet was discovered by John M. Wilcox and Norman F. Ness, who published their finding in 1965 [13].

The image above is a painting by NASA artist, Werner Heil. It was developed by Prof. John Wilcox as a tool for visualizing the surface that separates the two magnetic polarity regions produced by the Sun in the solar system. His concept was that a "baseball seam" shape located near the Sun separates the two magnetic hemispheres of the interplanetary medium; the shape was determined by the large-scale magnetic field at the Sun. That geometrical shape is carried radially outward by the solar wind. As the Sun, and the magnetic field configuration it generates, continue to rotate underneath the structure, the resulting surface becomes the one you see in the painting.[14]

Hannes Alfvén and Per Carlqvist speculate[15] on the existence of a galactic current sheet, a counterpart of the heliospheric current sheet, with an estimated galactic current of 1017 - 1019 Amps, that might flow in the plane of symmetry of the galaxy.

Found this video that exemplifies better how the heliospheric current sheet "travels" through space, from 2001 to 2009, interesting how it looks!

Mod's note: changed title from all caps.
Last edited by a moderator:


The Living Force
FOTCM Member
Re: Heliospheric current sheet

I just saw a video that relates to the Heliospheric current sheet (I was wondering why, for, menaning of it since I knew about it), it explains better and more about this particular sheet, talks about also about the uncoming flip on the sun's magnetic field. "Riding the wave", "Thershold" etc, concepts I read at the wave series, become more understandable, it helps to visualize such concepts. said:
The sun’s magnetic field is just too hypnotizing just before it shifts
By Strange Sounds - Apr 11, 2016

Something big is about to happen on the sun. The sun’s magnetic field is about to flip. And this change will have ripple effects throughout the solar system.

The sun’s magnetic field changes polarity approximately every 11 years. It happens at the peak of each solar cycle as the sun’s inner magnetic dynamo re-organizes itself. The coming reversal will mark the midpoint of Solar Cycle 24. Half of “solar max” will be behind us, with half yet to come.

A reversal of the sun’s magnetic field is, literally, a big event. The domain of the sun’s magnetic influence (also known as the “heliosphere”) extends billions of kilometers beyond Pluto. Changes to the field’s polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space.

When solar physicists talk about solar field reversals, their conversation often centers on the “current sheet.” The current sheet is a sprawling surface jutting outward from the sun’s equator where the sun’s slowly rotating magnetic field induces an electrical current. The current itself is small, only one ten-billionth of an amp per square meter (0.0000000001 amps/m2), but there’s a lot of it: the amperage flows through a region 10,000 km thick and billions of kilometers wide. Electrically speaking, the entire heliosphere is organized around this enormous sheet.

During field reversals, the current sheet becomes very wavy. (Heliospheric current sheet, it is explained at the video)

Cosmic rays are also affected. These are high-energy particles accelerated to nearly light speed by supernova explosions and other violent events in the galaxy. Cosmic rays are a danger to astronauts and space probes, and some researchers say they might affect the cloudiness and climate of Earth.

The current sheet acts as a barrier to cosmic rays, deflecting them as they attempt to penetrate the inner solar system. A wavy, crinkly sheet acts as a better shield against these energetic particles from deep space.

As the field reversal approaches, data from Wilcox show that the sun’s two hemispheres are out of synch.


The Living Force
FOTCM Member
Re: Heliospheric current sheet

I am not sure what really means or what would be the implications in a boarder sense -yet, I think, but, since is being reported, I am posting it here ... said:
SOLAR SECTOR BOUNDARY CROSSING (UPDATED): On April 29th or 30th, Earth will cross a fold in the heliospheric current sheet--a vast wavy structure in interplanetary space separating regions of opposite magnetic polarity. This is called a "solar sector boundary crossing," and it could trigger geomagnetic activity around Earth's poles. NOAA forecasters estimate a 60% chance of G1-class geomagnetic storms on April 29th.


Re: Heliospheric current sheet

Interesting stuff, thanks for posting mabar.

The patterns in the first video kind of reminded me of the patterns formed by cymatics.


The Living Force
FOTCM Member
Re: Heliospheric current sheet

Archaea said:
The patterns in the first video kind of reminded me of the patterns formed by cymatics.
Ah! ... had not been here for a while, I did not knew anything about cymatics, apart from wikipedia, found a quite an interesting and cool video!! Thanks Archaea!!, I really loved to see it!

I post it here, because from one way or another is related, also one way or another, is important the "developments"? of the Heliospheric current sheet ---although I am not sure to what extent, spaceweather mentioned about it, that would be a point, I think ... said:
SOLAR SECTOR BOUNDARY CROSSING: Late on May 25th, Earth will cross a fold in the heliospheric current sheet and enter a region of space filled with negative polarity magnetic fields. Such fields can open a crack in Earth's magnetosphere, allowing solar wind to pour in and fuel geomagnetic disturbances. According to NOAA forecasters, the odds of a G1-class storm is 20% to 30%. Aurora alerts: text, voice.


FOTCM Member
I changed the title of this thread to make it more generally about the sun.

Article about coronal hole here:

While the cause of coronal holes remains a mystery, they “correlate to areas on the sun where magnetic fields soar up and away, without looping back down to the surface, as they do elsewhere.”

Question is: where is that current flow going??? That's a pretty huge coronal hole.

Meanwhile, on spaceweather:

On May 23rd, an enormous swarm of sprites flickered and danced across the top of a thunderstorm in Oklahoma. Almost 400 miles away in New Mexico, amateur astronomer Thomas Ashcraft trained his cameras on the display. He captured the sprites--and something more:


There's a video available.

"Note the dendritic upward spray in the midst of the sprite cluster," points out Ashcraft. "That is a possible 'pop-through gigantic jet'--a rare event."

Ashcraft has posted a video of the event with VLF-ELF radio emissions he recorded as a soundtrack. Turn up the volume: "The deep bass sound of the lightning stroke sounds like a distant shotgun blast in the night," he says.

What is a pop-through gigantic jet? Lightning scientist Oscar van der Velde of the Technical University of Catalonia explains: "A cluster of sprites can actually warp Earth's ionosphere, bringing it down from its usual altitude of 90 km to only 40 km." This sets the stage for the jet.

"The sprite cluster triggers an upward-directed discharge which in the past received fancy names as 'troll' or 'palm tree'," says van der Velde. "A satellite-based study by Taiwanese researchers in 2012 found them similar to gigantic jets--large isolated discharges reaching from the thundercloud toward the ionosphere. In case of a 'pop-through gigantic jet,' the lowering of the ionosphere is not uniform and the jet may then reach higher than the bottom tendrils of the sprite."

Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. Now "sprite chasers" routinely photograph sprites--and more!--from their own homes. "They are easily detected by certain cameras," says van der Velde, "and if a storm is in the mood, you may record one every few minutes."


The Living Force
A rotating magnetic field with the positive/negative region alternating every 27 days, brushing all the planets as it goes..?

That first video showing the sheet spin over an 8 year span looked a great deal like some sinning component of an electric motor.

The more I learn about the electrical characteristics of our solar system, the more antiquated the official all-gravity model appears. And after seeing this, it struck me for the first time as feeling like one of those pre-Galilean models everybody smirks at in science classrooms today.


The Living Force
FOTCM Member said:
AURORA SURPRISE: No sunspots. No solar flares. No gust of solar wind. In short, there was no reason to expect an outburst of auroras on Feb. 17th. Then this happened



Solar minimum is here - but even now strangely beautiful auroras are dancing around the poles. Deep inside the Arctic Circle, the expert guides of Aurora Holidays in Utsjoki, Finland, can help you chase them. Book now!


COSMIC RAYS ARE PEAKING: Once again, cosmic rays percolating through Earth's atmosphere are within a percentage point of the Space Age maximum. This is a symptom of Solar Minimum. When the sun's magnetic field weakens, it allows deep space radiation to enter the solar system. The current Solar Minimum is very deep, and consequently cosmic rays fluxes are very high. You can track the numbers right here on​

STARLINK BUZZES PUERTO RICO: SpaceX successfully launched another batch of 60 Starlink satellites on Feb. 17th. Just hours after the Falcon 9 rocket blasted off from Cape Canaveral, the newly released satellites flew over Puerto Rico where a meteor camera captured them flying single-file across the sky:​

The camera is operated by the Astronomical Society of the Caribbean (Sociedad de Astronomia del Caribe), the largest astronomy group on the Island. "A couple of flashes are visible ahead of the main group of satellites, perhaps from parts or a pair of Starlink satellites ahead of the others," notes the Society.​

This latest launch brings the total number of Starlink satellites in orbit to 300--a number that could grow to 42,000 by the time the Starlink project is complete. The good news is, Starlink could bring internet access to every corner of the world. The bad news is, Starlink poses a serious threat to astronomical research according to a recent study by the International Astronomical Union.

See for yourself. Starlink flyby predictions are available from Calsky and Heavens Above. (Got pictures? Submit them here.)

AURORA SURPRISE: No sunspots. No solar flares. No gust of solar wind. In short, there was no reason to expect an outburst of auroras on Feb. 17th. Then this happened:​

"Surprise auroras strike big!" exclaims Alexander Kuznetsov, who photographed the display from Kilpisjärvi, Finland. "At one point they went pink and moved very fast! I also saw a fast corona unfolding above me, reminding me of an angel."​

"When I first went outside, I was not expecting much because the solar wind speed was relatively low, so I did not take my snowshoes," he says. "Then the show began. Currently, there is over a meter of snow in Kilpisjärvi, so I had to crawl through some snowy terrain to get to the best viewing spot."

Where did these auroras come from? A crack opened in Earth's magnetic field (that is, "BsubZ tilted south"). Solar wind poured in to fuel the display--no solar storm required. said:
The Sun is a big magnet.

During solar minimum the Sun's magnetic field, like Earth's, resembles that of an iron bar magnet, with great closed loops near the equator and open field lines near the poles. Scientists call such a field a "dipole." The Sun's dipolar field is about as strong as a refrigerator magnet, or 50 gauss. Earth's magnetic field is 100 times weaker.

During the years around solar maximum (2000 and 2001 are good examples) spots pepper the face of the Sun. Sunspots are places where intense magnetic loops -- hundreds of times stronger than the ambient dipole field -- poke through the photosphere. Sunspot magnetic fields overwhelm the underlying dipole; as a result, the Sun's magnetic field near the surface of the star becomes tangled and complicated.

The Sun's magnetic field isn't confined to the immediate vicinity of our star. The solar wind carries it throughout the solar system. Out among the planets we call the Sun's magnetic field the "Interplanetary Magnetic Field" or "IMF." Because the Sun rotates (once every 27 days) the IMF has a spiral shape -- named the "Parker spiral" after the scientist who first described it.
Earth has a magnetic field, too. It forms a bubble around our planet called the magnetosphere, which deflects solar wind gusts. (Mars, which does not have a protective magnetosphere, has lost much of its atmosphere as a result of solar wind erosion.) Earth's magnetic field and the IMF come into contact at the magnetopause: a place where the magnetosphere meets the solar wind. Earth's magnetic field points north at the magnetopause. If the IMF points south -- a condition scientists call "southward Bz" -- then the IMF can partially cancel Earth's magnetic field at the point of contact.

"When Bz is south, that is, opposite Earth's magnetic field, the two fields link up," explains Christopher Russell, a Professor of Geophysics and Space Physics at UCLA. "You can then follow a field line from Earth directly into the solar wind" -- or from the solar wind to Earth. South-pointing Bz's open a door through which energy from the solar wind can reach Earth's atmosphere!

Southward Bz's often herald widespread auroras, triggered by solar wind gusts or coronal mass ejections that are able to inject energy into our planet's magnetosphere. said:
The interplanetary magnetic field (IMF) is a part of the Sun's magnetic field that is carried into interplanetary space by the solar wind. The interplanetary magnetic field lines are said to be "frozen in" to the solar wind plasma. Because of the Sun's rotation, the IMF, like the solar wind, travels outward in a spiral pattern that is often compared to the pattern of water sprayed from a rotating lawn sprinkler. The IMF originates in regions on the Sun where the magnetic field is "open"--that is, where field lines emerging from one region do not return to a conjugate region but extend virtually indefinitely into space. The direction (polarity, sense) of the field in the Sun's northern hemisphere is opposite that of the field in the southern hemisphere. (The polarities reverse with each solar cycle.)

The heliospheric current sheet

Along the plane of the Sun's magnetic equator, the oppositely directed open field lines run parallel to each other and are separated by a thin current sheet known as the "interplanetary current sheet" or "heliospheric current sheet" (see the figure above). The current sheet is tilted (because of an offset between the Sun's rotational and magnetic axes) and warped (because of a quadrupole moment in the solar magnetic field) and thus has a wavy, "ballerina skirt"-like structure as it extends into interplanetary space (see the figure on the left). Because the Earth is located sometimes above and sometimes below the rotating current sheet, it experiences regular, periodic changes in the polarity of the IMF. These periods of alternating positive (away from the Sun) and negative (toward the Sun) polarity are known as magnetic sectors.


The IMF is a vector quantity with three directional components, two of which (Bx and By) are oriented parallel to the ecliptic. The third component--Bz--is perpendicular to the ecliptic and is created by waves and other disturbances in the solar wind. When the IMF and geomagnetic field lines are oriented opposite or "antiparallel" to each other, they can "merge" or "reconnect," resulting in the transfer of energy, mass, and momentum from the solar wind flow to magnetosphere The strongest coupling --with the most dramatic magnetospheric effects-- occurs when the Bz component is oriented southward.

The IMF is a weak field, varying in strength near the Earth from 1 to 37 nT, with an average value of ~6 nT.


The Living Force
FOTCM Member
A filament located towards the southwest limb just erupted and flung a large amount of plasma away from the Sun within the past hour. A coronal mass ejection (CME) is pretty much certain, but is likely aimed away from our planet. Still a nice event on the Sun. Image by GOES-16 SUVI.



The Living Force
FOTCM Member
The three main players on the visible disk on Monday.

AR 2936 did show some decay today and separation between the leader and trailing spots of the group. Despite this, this region will remain an ongoing threat for minor C-Flares and perhaps another isolated M-Flare. In the southeast quadrant, AR 2939 appears to be stable as far as growth is concerned and has produced a few small B-Flares.In the northeast, AR 2940 is showing a little bit of promise as it appears to be expanding and has produced occasional minor C-Flares. All three regions will continue to be monitored as they rotate across the Earth facing side of the Sun. Imagery courtesy of SDO/HMI.



The Living Force
FOTCM Member
Moderate Geomagnetic Storm Watch.

The coronal mass ejection (CME) observed following the long duration M1.1 flare around AR 2936 is predicted to reach Earth by February 2nd. A moderate (G2) level geomagnetic storm watch was officially added by the NOAA Space Weather Prediction Center (SWPC). Aurora sky watchers from middle to high latitudes should be alert during the next 48 hours.

I know I've been quiet lately, but fear not--I'm still here. At the balmy temp of -29F, I decided not to stay out too long last night but I could not resist the lure of night sky (even after I nearly froze my fingers off when the lights started to rip across the sky when I wasn't expecting it and wasn't properly gloved). Enjoy!

January 30, 2022
Goldstream Valley aurora - Fairbanks, AK


The Living Force
FOTCM Member
A few things happening this evening. The expected CME produced by the M1 solar flare on Jan 29 was detected by both the ACE and DSCOVR spacecrafts. The interplanetary shockwave passed Earth at 22:21 UTC (Feb 1). A minor (G1) geomagnetic storm watch is currently in effect.

SUMMARY: Geomagnetic Sudden Impulse
Observed: 2022 Feb 01 2221 UTC
Deviation: 22 nT
Station: Honolulu

Secondly, a near M-Flare (C9.0) was just observed around AR 2939 in the southeast quadrant.

Space Weather by SolarHam

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