Sunspots rule the visible solar disc, again. On 10 September, a 'new' sunspot region rotated into view in the southern solar hemisphere, around the Eastern limb. This sunspot region became NOAA Active Region 1106, but originally was numbered 1100, back in August. On September 15/16, another sunspot region rotated into view (further south than AR 1106). The spot appears well-formed, and there are at least two sunspot groups in this region. The coming days should see an increase in the background X-ray flux, and the 10.7-cm flux (will we see a 10.7-cm flux in the 90s?). All of this means a higher ionization of the F-region of the Ionosphere, resulting in more stable shortwave radio signal propagation over most paths. Since the geomagnetic field is expected to remain at quiet levels, the propagation of signals will be stable and reliable, over paths normally expected to be open at this time of year with this level of sunspot activity.

Below: A close-up view of the new sunspot: This is a false-color image at the 4500-Angstrom wavelength. (1300 UTC, September 16, 2010)

Below: A close-up view of Active Sunspot Region (NOAA) 1106: This is a false-color image at the 4500-Angstrom wavelength. (1300 UTC, September 16, 2010)

Below: The view of the active sunspot regions on September 16, 2010 at 0234 UTC by SDO AIA at 304 Angstroms

Below: The view of the active sunspot regions on September 16, 2010 at 0217 UTC by SDO AIA at 171 Angstroms

More about Background X-rays

Overall, the monthly average background 'hard' X-ray level is rising (as seen by the following plot), showing a change from deep solar cycle minimum. We are certainly in the rising phase of Sunspot Cycle 24. While it has been a slow up-tick over the last eighteen months, I expect to see a more rapid rise during late 2010, and through 2011.

For reference on Ionospheric propagation, including how background X-ray influences Ionospheric conditions, see this reference by the late Bob Brown, NM7M, Ph.D. from U.C.Berkeley.

There's been a lot of sensationalism in the News, since the solar events erupting on August 1, 2010.  For instance, a news article on the Telegraph.co.uk News website states, "The earth could be hit by a wave of violent space weather as early as Tuesday after a massive explosion of the sun, scientists have warned."  Are we really in the path of a massive explosion that could signal global devastation?

The facts

At approximately 0855 UTC on August 1, 2010, a C3.2 magnitude soft X-ray flare erupted from NOAA Active Sunspot Region 11092 (1092).  At nearly the same time, a massive filament eruption occurred.

Prior to the filament's eruption, NASA's Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) instruments revealed an enormous plasma filament stretching across the sun's northern hemisphere. When the EIT wave triggered by the C3.2-class X-ray explosion plowed through this filament after rippling through the corona, it appears to have caused the filament to erupt, sending out a huge plasma cloud (a coronal mass ejection, or CME).

An EIT wave can be seen emerging from the origin of the X-ray flare and sweeping across the sun's northern hemisphere into the filament field. The impact of this EIT wave may well have propelled the filament into space. The movies (see links, below) seem to support the conclusion that both eruptions, occurring together, are linked, despite the approximately 400,000 kilometer distance between the flare and the filament eruption. How can this be? While we cannot always see the magnetic field lines between solar features (magnetic field lines are not visible unless there is plasma trapped along these field lines), we can assume from this event that huge connecting field lines existed between the sunspot region and the filament in the sun's northern hemisphere.

This is an amazing event. A complex series of eruptions involving most of the visible surface of the sun has occurred, ejecting plasma toward the Earth. This coronal mass ejection (CME) rides the solar wind. Depending on the speed of the solar wind and the ejected plasma, this cloud will reach Earth's magnetosphere sometime between August 3 and August 5. High-latitude sky watchers should be alert for auroras. Radio communications by way of the ionosphere may become degraded soon after the CME arrives, and the degraded conditions may last for up to three days.

Detailed analysis and discussion

Detailed analysis from the complex multi-eruption solar event of Aug 1</b> (C-class flare and filament eruption) indicates that the flare produced a CME that is partially Earth-directed (some of the plasma may miss the Earth when it arrives). This CME appears to be moving at a very high speed, expected to arrive by end of Aug 2 or by start of Aug 3.  The analysis also indicates that the filament eruption also released a slower-moving CME, that is fully Earth-facing.  This second CME should reach Earth by Aug 4, causing an increase in geomagnetic disturbance.  Of course, the geomagnetic activity level only increases if these CMEs are magnetically configured so that they connect with Earth's magnetosphere (specifically, the Bz component of the solar wind and the CME must be negative, or oriented southward).  If they do not connect magnetically, then the CMEs will have minimal influence on the geomagnetic field.

The energy that will likely be transferred by the plasma mass that was ejected by the two eruptions (first, the slower-moving coronal mass ejection originating in the C-class X-ray flare at sunspot region 1092, and, second, the faster-moving plasma ejection originating in the filament eruption) is at most 'moderate'. This event was rather low in energy. It will not result in any news-worth events on Earth (no laptops will be fried, no power grids will fail).

There are two periods during the 12-months of each year during which aurora is most likely to occur.  These are the Spring and Autumn equinoctial months of March and September ( see Equinox on Wikipedia ).  Understand that I am not saying that aurora does not occur during other months of the year.  Yes, aurora may occur during any month of the year.

However, the probability of occurrence, as well as the strength and frequency of aurora tends to increase during the two periods discussed.  This is more easily observed during solar cycle minimum years, when there is very little solar activity that would provide the ingredients for auroral events.  The probability for these two CMEs from August 1st is not as strong as it would be, say, during the end of September.

Since we're only at the beginning of August, the coronal mass ejections racing toward Earth may not result in much of any energy transfer from the solar wind into the Earth's magnetosphere.  The first CME was not even fully Earth-directed, so some of that will miss Earth.  That one arrives sometime toward the end of August 2, or during the start of August 3.  The second CME was large, but slower.  It was fully-Earth directed as far as can be detected.  When this second plasma cloud and its shockwave hits the magnetosphere that shields the Earth, it will have some connection and transfer of energy.  How much is yet to be seen.

In the worst-case scenario, it will depress the ionospheric ionization by as much as 40 percent, really degrading shortwave comms.  That would also trigger energetic aurora that could be visible in the lower latitudes, and provide good VHF propagation.  However, it is possible that the impact will NOT have that much magnetic interconnection.  Watch the Bz component of the solar wind, once the CMEs hit.

There are a lot of factors that must be 'just right' in order to trigger the 'massive' once-in-a-cycle extreme geomagnetic storm.  This event was not that extreme, so it is unlikely that it will result in severe or even strong geomagnetic activity.  We'll see, of course.  I could be wrong.  There is no way to know until the two shockwaves arrive at the GEOS satellite that can detect the magnetic orientation of these interplanetary coronal mass ejections, as well as their speed and temperatures.  Be watching this website for the details over the next 36 hours.

The following was added in a later edit to this article:

I want to be clear that my main issue is not the use of "solar tsunami" when describing the wave seen propagating away from the first flare, but with the prediction by News reporters of massive, violent "space weather" that will cause very noticeable effects on Earth (power grids blowing, satellites burning up, and so on).

The leap is made by the media because solar scientists recently held conferences where they discussed the impact of that once-in-a-century extreme space weather storm caused by incredibly large solar flares (of the X-class magnitude) that are Earth-directed. These reporters see the snippet of news on SpaceWeather.com about a massive solar eruption that covers most of the visible Sun, and they connect the two into a resulting News story that this space weather event could be "the big one".

The leap is made by the media because solar scientists recently held conferences where they discussed the impact of that once-in-a-century extreme space weather storm caused by incredibly large solar flares (of the X-class magnitude) that are Earth-directed. These reporters see the snippet of news on SpaceWeather.com about a massive solar eruption that covers most of the visible Sun, and they connect the two into a resulting News story that this space weather event could be "the big one".

This is what I am calling "Bunk". The August 1 double eruption event was, in the grand view, a rather small event. We've seen much more powerful events in the recorded history of flares, filament eruptions, and coronal mass ejections.

The X-ray flare (first event) was on the lower end of the C-class scale. When it occurred, it barely caused any shortwave signal fading on the sunlit side of the Earth, because it was a weak X-ray flare. The plasma released was not noticeably huge, either.

What's more, that first CME does not appear to be fully Earth-directed. A good portion may well miss the Earth when it "arrives" sometime today or tomorrow. It is fast-moving (in comparison with average CME speeds).

In the movie of the event, the "tsunami" wave moves along the "surface" of the corona. It does NOT ripple out into interplanetary space (as many news stories claim), so it is not a tsunami wave headed toward Earth resulting in some major Earthly destruction. The "coronal tsunami" is a wave that triggered a second eruption. A lot of the news stories floating around on the 'net are plain wrong (like the Telegraph.co.uk story that actually says that the solar tsunami is heading toward Earth, and we're bracing for the worst!).

A reference about these solar tsunami events is here: NASA - Mystery of Solar Tsunami--Solved

(Just to be sure this is clear: SpaceWeather.com did not invent the term. They accurately described the wave in the movie. I was not calling SpaceWeather.com's report as BUNK).

The bigger and more noticeable eruption was that of the massive filament (triggered by the "tsunami"). This released a massive cloud of solar plasma, fully Earth-directed. This is a slow-moving CME. It is large, but slow, so it will most likely cause a moderate shock when it impacts the Earth's magnetosphere. If it is magnetically aligned such that it connects with the magnetosphere, it can trigger moderate geomagnetic disturbances, in turn triggering aurora. It is fairly unlikely to cause massive power grid outages and other ill effects. There is a good chance, based on the origin of the CME, that it will NOT be fully aligned to connect with the magnetosphere. We won't know until it passes the GEOS spacecraft and we get readings.

Again, the sensationalist headlines and stories are "BUNK". Not the movie nor the analysis by SpaceWeather.com - their description was pretty "spot on" (pardon the pun).

73 de NW7US

The following Edit is post-event, and added on August 6, 2010:

(under review, pending publishing, today - stay tuned!)

HF Conditions Fair

The background hard X-rays (see below) are still somewhat elevated. HF propagation is mostly normal over most paths. However, we expect an increase in the geomagnetic activity in the next 48 hours due to the influence of a coronal hole.

For reference on Ionospheric propagation, including how background X-ray influences Ionospheric conditions, see this reference by the late Bob Brown, NM7M, Ph.D. from U.C.Berkeley.

The large coronal hole, seen below, is now in position to affect ionospheric propagation. HF (shortwave) communications will suffer, today (15 June 2010) through the next three days, due to the influence of this large coronal hole on the Sun. Coronal holes are large regions in the corona that are less dense and cooler than surrounding areas. The open structure of their magnetic field allows a constant flow of high-density plasma to stream out of the holes. There is an increase in the intensity of the solar wind effects on Earth when a coronal hole faces us.

Magnetic Field Lines of Active Sunspot Region (NOAA) 1081

This is a breath-taking view of the plasma and magnetic structures rising out from AR 1081.

The new sunspot region that I reported yesterday, is now numbered as Catania 74. As seen at the 4500 Angstrom filtered view, this new sunspot region is growing, today. Note that this is not a returning old sunspot region. It is new, and in the southern hemisphere. The possible return of sunspot region 1069 may rotate into view in about two days' time.

This new sunspot region, with the growth seen so far, may become a significant region with possible flaring activity. At the moment, however, only moderate C-class flares may occur.

Here is the SDO AIA image, at 4500 A (click for large view):