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Space Weather. The Sun-Earth Connection. Ionospheric radio propagation. Solar storms. Coronal Mass Ejections (CMEs). Solar flares and radio blackouts. All of these topics are interrelated for the amateur radio operator, especially when the activity involves the shortwave, or high-frequency, radiowave spectrum.

Learning about space weather and radio signal propagation via the ionosphere aids you in gaining a competitive edge in radio DX contests. Want to forecast the radio propagation for the next weekend so you know whether or not you should attend to the Honey-do list, or declare a radio day?

In the last ten years, amazing technological advances have been made in heliophysics research and solar observation. These advances have catapulted the amateur radio hobbyist into a new era in which computer power and easy access to huge amounts of data assist in learning about, observing, and forecasting space weather and to gain an understanding of how space weather impacts shortwave radio propagation, aurora propagation, and so on.

I hope to start “blogging” here about space weather and the propagation of radio waves, as time allows. I hope this finds a place in your journey of exploring the Sun-Earth connection and the science of radio communication.

With that in mind, I’d like to share some pretty cool science. Even though the video material in this article are from 2010, they provide a view of our Sun with the stunning solar tsunami event:

On August 1, 2010, the entire Earth-facing side of the sun erupted in a tumult of activity. There was a C3-class solar flare, a solar tsunami, multiple plasma-filled filaments of magnetism lifting off the stellar surface, large-scale shaking of the solar corona, radio bursts, a coronal mass ejection and more!

At approximately 0855 UTC on August 1, 2010, a C3.2 magnitude soft X-ray flare erupted from NOAA Active Sunspot Region 11092 (we typically shorten this by dropping the first digit: NOAA AR 1092).

At nearly the same time, a massive filament eruption occurred. Prior to the filament’s eruption, NASA’s Solar Dynamics Observatory (SDO) AIA instruments revealed an enormous plasma filament stretching across the sun’s northern hemisphere. When the solar shock wave triggered by the C3.2-class X-ray explosion plowed through this filament, it caused the filament to erupt, sending out a huge plasma cloud.

In this movie, taken by SDO AIA at several different Extreme Ultra Violet (EUV) wavelengths such as the 304- and 171-Angstrom wavelengths, a cooler shock 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 shock wave may propelled the filament into space.

This movie seems to support this analysis: Despite the approximately 400,000 kilometer distance between the flare and the filament eruption, they appear to erupt together. How can this be? Most likely they’re connected by long-range magnetic fields (remember: we cannot see these magnetic field lines unless there is plasma riding these fields).

In the following video clip, taken by SDO AIA at the 304-Angstrom wavelength, a cooler shock 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 shock wave propelled the filament into space. This is in black and white because we’re capturing the EUV at the 304-Angstrom wavelength, which we cannot see. SDO does add artificial color to these images, but the raw footage is in this non-colorized view.

The followling video shows this event in the 171-Angstrom wavelength, and highlights more of the flare event:

The following related video shows the “resulting” shock wave several days later. Note that this did NOT result in anything more than a bit of aurora seen by folks living in high-latitude areas (like Norway, for instance).

This fourth video sequence (of the five in the first video shown in this article) shows a simulation model of real-time passage of the solar wind. In this segment, the plasma cloud that was ejected from this solar tsunami event is seen in the data and simulation, passing by Earth and impacting the magnetosphere. This results in the disturbance of the geomagnetic field, triggering aurora and ionospheric depressions that degrade shortwave radio wave propagation.

At about 2/3rd of the way through, UTC time stamp 1651 UTC, the shock wave hits the magnetosphere.

This is a simulation derived from satellite data of the interaction between the solar wind, the earth’s magnetosphere, and earth’s ionosphere. This triggered aurora on August 4, 2010, as the geomagnetic field became stormy (Kp was at or above 5).

While this is an amazing event, a complex series of eruptions involving most of the visible surface of the sun occurred, ejecting plasma toward the Earth, the energy that was 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) was “moderate.” This event, especially in relationship with the Earth through the Sun-Earth connection, was rather low in energy. It did not result in any news-worthy events on Earth–no laptops were fried, no power grids failed, and the geomagnetic activity level was only moderate, with limited degradation observed on the shortwave radio spectrum.

This “Solar Tsunami” is actually categorized as a “Moreton wave”, the chromospheric signature of a large-scale solar coronal shock wave. As can be seen in this video, they are generated by solar flares. They are named for American astronomer, Gail Moreton, an observer at the Lockheed Solar Observatory in Burbank who spotted them in 1959. He discovered them in time-lapse photography of the chromosphere in the light of the Balmer alpha transition.

Moreton waves propagate at a speed of 250 to 1500 km/s (kilometers per second). A solar scientist, Yutaka Uchida, has interpreted Moreton waves as MHD fast-mode shock waves propagating in the corona. He links them to type II radio bursts, which are radio-wave discharges created when coronal mass ejections accelerate shocks.

I will be posting more of these kinds of posts, some of them explaining the interaction between space weather and the propagation of radio signals.

For live space weather and radio propagation, visit http://SunSpotWatch.com/. Be sure to subscribe to my YouTube channel: https://YouTube.com/NW7US.

The fourth video segment is used by written permission, granted to NW7US by NICT. The movie is copyright@NICT, Japan. The rest of the video is courtesy of SDO/AIA and NASA. Music is courtesy of YouTube, from their free-to-use music library. Video copyright, 2015, by Tomas Hood / NW7US. All rights reserved.

Here is this week’s space weather and geophysical report, issued 2015 Aug 03 0155 UTC.

Highlights of Solar and Geomagnetic Activity 27 July – 02 August 2015

Solar activity was dominated by B-class flare activity (very low levels) throughout the majority of the summary period, however, Region 2390 (S17, L=199, class/area=Dai/170 on 27 Jul) produced a single C1 flare (low levels) at 01/2005 UTC, which was the largest event of the period. No Earth-directed coronal mass ejections (CMEs) were observed during the summary period.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at normal levels on 31 Aug with moderate levels observed throughout the remainder of the summary period.

Geomagnetic field activity reached active levels on 27, 30-31 Jul and 02 Aug in response to an enhanced solar wind environment caused by the influence of multiple weak coronal hole high speed streams (CH HSSs). Geomagnetic field activity remained at quiet to unsettled levels throughout the remainder of the summary period.

Forecast of Solar and Geomagnetic Activity 03 August – 29 August 2015

Solar activity is expected to be at very low (B-class flare activity) to low levels (C-class flare activity) throughout the outlook period.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at moderate levels on 07-08, 17-21, 23, and 26-29 Aug in response to enhanced geomagnetic field activity cause by the influence of multiple recurrent coronal hole high speed streams (CH HSSs). High electron flux levels are expected for the remainder of the outlook period.

Geomagnetic field activity is expected to reach G1 (Minor) geomagnetic storm levels on 28 Aug with active levels expected on 06-07, 17, 20, 26-27, and 29 Aug, all due to the influence of multiple recurrent CH HSSs. The geomagnetic field is expected to be at quiet to unsettled levels throughout the remainder of the outlook period.

Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/

Live Aurora mapping is at http://aurora.sunspotwatch.com/

If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx

Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!

Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g

We’re on Facebook: http://NW7US.us/swhfr

Watch this video on a large screen. (It is HD). Discuss. Share.

This video features stunning clips of the Sun, captured by SDO from each of the five years since SDO’s deployment in 2010. In this movie, watch giant clouds of solar material hurled out into space, the dance of giant loops hovering in the corona, and huge sunspots growing and shrinking on the Sun’s surface.

April 21, 2015 marks the five-year anniversary of the Solar Dynamics Observatory (SDO) First Light press conference, where NASA revealed the first images taken by the spacecraft. Since then, SDO has captured amazingly stunning super-high-definition images in multiple wavelengths, revealing new science, and captivating views.

February 11, 2015 marks five years in space for NASA’s Solar Dynamics Observatory, which provides incredibly detailed images of the whole Sun 24 hours a day. February 11, 2010, was the day on which NASA launched an unprecedented solar observatory into space. The Solar Dynamics Observatory (SDO) flew up on an Atlas V rocket, carrying instruments that scientists hoped would revolutionize observations of the Sun.

Capturing an image more than once per second, SDO has provided an unprecedentedly clear picture of how massive explosions on the Sun grow and erupt. The imagery is also captivating, allowing one to watch the constant ballet of solar material through the sun’s atmosphere, the corona.

The imagery in this “highlight reel” provide us with examples of the kind of data that SDO provides to scientists. By watching the sun in different wavelengths (and therefore different temperatures, each “seen” at a particular wavelength that is invisible to the unaided eye) scientists can watch how material courses through the corona. SDO captures images of the Sun in 10 different wavelengths, each of which helps highlight a different temperature of solar material. Different temperatures can, in turn, show specific structures on the Sun such as solar flares or coronal loops, and help reveal what causes eruptions on the Sun, what heats the Sun’s atmosphere up to 1,000 times hotter than its surface, and why the Sun’s magnetic fields are constantly on the move.

Coronal loops are streams of solar material traveling up and down looping magnetic field lines). Solar flares are bursts of light, energy and X-rays. They can occur by themselves or can be accompanied by what’s called a coronal mass ejection, or CME, in which a giant cloud of solar material erupts off the Sun, achieves escape velocity and heads off into space.

This movie shows examples of x-ray flares, coronal mass ejections, prominence eruptions when masses of solar material leap off the Sun, much like CMEs. The movie also shows sunspot groups on the solar surface. One of these sunspot groups, a magnetically strong and complex region appearing in mid-January 2014, was one of the largest in nine years as well as a torrent of intense solar flares. In this case, the Sun produced only flares and no CMEs, which, while not unheard of, is somewhat unusual for flares of that size. Scientists are looking at that data now to see if they can determine what circumstances might have led to flares eruptions alone.

Scientists study these images to better understand the complex electromagnetic system causing the constant movement on the sun, which can ultimately have an effect closer to Earth, too: Flares and another type of solar explosion called coronal mass ejections can sometimes disrupt technology in space as well as on Earth (disrupting shortwave communication, stressing power grids, and more). Additionally, studying our closest star is one way of learning about other stars in the galaxy.

Goddard built, operates and manages the SDO spacecraft for NASA’s Science Mission Directorate in Washington, D.C. SDO is the first mission of NASA’s Living with a Star Program. The program’s goal is to develop the scientific understanding necessary to address those aspects of the sun-Earth system that directly affect our lives and society.

https://www.youtube.com/watch?v=zXN-MdoGM9g

Watch this amazing explosion on the Sun. From sunspot complex 1226-1227 comes an X-ray Flare peaking at a magnitude of M2.5 at 0640 UTC on 7 June, 2011.

Source: https://www.youtube.com/watch?v=KQMrRu8BWDo

This X-ray flare hurled a massive coronal mass ejection (CME) toward the Earth. This not-squarely Earth-directed CME is moving at 1400 km/s according to NASA models. The CME did not deliver even a noticeable glancing blow to Earth’s magnetic field late June 8th or June 9th.

What can be seen clearly in this movie is one of the most spectacular prominence eruptions ever observed. In fact, one could call it a “prominence explosion”. The prominence material expanded to a volume some 75 times as big across as the earth!

This X-ray flare also triggered an S1-level solar radiation storm, causing a long-lasting polar cap absorption (PCA) event. A polar cap absorption (PCA) event affects the propagation of a shortwave radio signal as it makes its way over the polar regions. In short, radio communications on lower shortwave radio frequencies become more difficult, as those radio signals are absorbed by the ionosphere (in the D-region) over the polar regions.

What does this mean in real-world communications? Trans-polar airline pilots may find it more difficult to communicate with regional air traffic control, shortwave radio listeners who want to hear a broadcast from a country by receiving a transmission from a country by way of a transmission beamed over the pole (like, from Europe into the USA via the North Pole), or other such communications, will find those signals all but gone. The stronger the PCA event, the higher the frequencies absorbed over the polar regions, with the greatest absorption occurring at the lower frequencies.

This movie spans the period of time from 0300 UTC through 1556 UTC, and is composed of the 171-Angstrom, 304-Angstrom, and 335-Angstrom wavelength views as captured by the filters of the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA). In this movie, the AIA instruments capture the Sun’s extreme ultraviolet light and reveal a very large eruption of cool gas. It is somewhat unique because at many places in the eruption there seems to be even cooler material–at temperatures less than 80,000 K.

The following is a linked video that is part of this event: http://www.youtube.com/watch?v=L4CsjcUGoaw

Watch as we zoom out to see a total view of the June 7, 2011 moderately-powerful X-ray Flare and Prominence Eruption. This movie will give you a full perspective of the immense size of this prominence eruption as it spews out away from the Sun.

The X-ray Flare peaked at a moderate magnitude of M2.5 at 0640 UTC, but unleashed a huge prominence eruption. The massive cloud of plasma was ejected out into interplanetary space, but missed the Earth. This movie stars with a “close-up” view by the Solar Dynamics Observatory at a combined wavelength view at 94 and 304 Angstroms. Then, the movie views the event further back through the eyes of the COR1 spacecraft (with the SDO AIA 304 image superimposed in the middle). Next, we zoom out to the COR2 spacecraft and superimpose the COR1 and SDO views. Then, we zoom further back to the H1 view… and finally look again at the event close-up.

More info: http://sunspotwatch.com/

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Source: SDO AIA NASA SOHO

Here is this week’s space weather and geophysical report, issued 2015 Jul 27 0117 UTC.

Highlights of Solar and Geomagnetic Activity 20 – 26 July 2015

Solar activity reached low levels this period. Region 2389 (S11, L=164, class/area=Dai/80 on 25 Jul) produced three low-level C-class flares throughout the period which were the largest observed events. Region 2389 produced a C1 flare at 24/0315 UTC, a C2/Sf flare at 24/1444 UTC, and a C1 flare at 26/1234 UTC but none of these events resulted in coronal mass ejections (CMEs) that were Earth-directed. Region 2390 (S15, L=198, class/area=Dac/130 on 26 Jul) underwent moderate penumbral development and increased in magnetic complexity late in the period, but remained largely unproductive. No Earth-directed CMEs were detected in SOHO/LASCO coronagraph imagery throughout the period.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 20, 26 Jul with moderate levels observed on 21-22, and 24-25 Jul. The electron flux decreased to normal levels on 23 Jul in response to enhanced geomagnetic field activity attributed to a combination of CME and coronal hole high speed stream (CH HSS) influence.

Geomagnetic field activity reached active to G1 (Minor) geomagnetic storm levels on 23 Jul due to a combination of the arrival of the 19 Jul CME (filament eruption) and the onset of a weak positive polarity CH HSS. Active conditions were observed at 23/0300-0600 UTC and 23/1800-2100 UTC and G1 storm conditions were observed at 23/0600-0900 UTC. The geomagnetic field was at quiet or quiet to unsettled levels for the remainder of the period under an ambient solar wind environment followed by weak CH HSS influence.

Forecast of Solar and Geomagnetic Activity 27 July – 22 August 2015

Solar activity is expected to be at very low to low levels throughout the period with a slight chance of M-class (R1-R2/Minor-Moderate) flare activity between 28 Jul-10 Aug due to the return of Region 2381 (N14, L=074) which produced two M-class flares last rotation.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at normal to moderate levels on 29 Jul, 01, 07, and 17 Aug with high levels expected throughout the remainder of the period.

Geomagnetic field activity is likely to reach G1 (Minor) geomagnetic storm levels on 07 Aug with active levels expected on 29 Jul, 02, 08-09, and 19 Aug, all in response to the influence of recurrent CH HSS. Quiet to unsettled geomagnetic field activity is expected throughout the remainder of the period under an ambient solar wind environment.

Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/

Live Aurora mapping is at http://aurora.sunspotwatch.com/

If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx

Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!

Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g

We’re on Facebook: http://NW7US.us/swhfr

Here is this week’s space weather and geophysical report, issued 2015 Jul 20 0508 UTC.

Highlights of Solar and Geomagnetic Activity 13 – 19 July 2015

Solar activity began the period at very low levels on 13 Jul but increased to low levels on 14 Jul with C1 flares from Region 2381 (N14, L=074, class/area Eko/550 on 08 Jul) and 2387 (N17, L=271, class/area Dai/120 on 18 Jul) at 14/0925 UTC and 14/1210 UTC respectively. Very low levels were observed on 15-17 Jul. Ground observatories reported a 22 degree filament eruption, centered near N39E36 at 16/1453-1643 UTC. The associated CME was not geoeffective. Region 2388 (N08, L=024, class/area Cao/020 on 16 Jul) produced a C1 flare at 18/1442 UTC and was accompanied by a Type II radio sweep (est speed 418 km/s). A CME was later observed in SOHO/LASCO C2 coronagraph imagery erupting from the west limb at 18/1512 UTC with an estimated plane of sky speed of 337 km/s. This event is not expected to be geoeffective. A long duration event (LDE) C2 flare was observed at 19/1040 UTC. The LDE was associated with a 23 degree long filament eruption located in the SW quadrant centered near S32W52. CME analysis, and subsequent WSA-Enlil model output, revealed a possible weak glancing blow from the northern flank of the SW-directed CME expected to arrive at Earth early on 23 Jul.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at moderate levels on 13 Jul. High levels were reached from 14-19 Jul due to effects from a coronal hole high speed stream.

Geomagnetic field activity reached minor storm levels on 13 Jul due to effects from a positive polarity coronal hole high speed stream. Mostly quiet conditions with isolated unsettled periods were observed from 14-16 Jul as coronal hole effects subsided. Quiet conditions were observed for the remainder of the period.

Forecast of Solar and Geomagnetic Activity 20 July – 15 August 2015

Solar activity is expected to be very low to low from 20-27 Jul. Moderate levels are likely from 28 Jul through 10 Aug due to the return of old Region 2381 followed by a return to very low to low levels for the remainder of the period.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to remain at high levels from 20-22 Jul before an anticipated glancing blow from the 19 Jul CME is expected to redistribute. Normal to moderate levels are expected from 23-26 Jul followed by a return to high levels from 27-30 Jul following elevated wind speeds from a combination of the CME and a positive polarity coronal hole high speed stream (CH HSS). High flux levels are expected from 03-05 Aug and 10-15 Aug following recurrent negative and positive polarity high speed streams respectively.

Geomagnetic field activity is expected to be at quiet to active levels on 20 Jul due to influence from a positive polarity CH HSS followed by quiet conditions from 21-22 Jul as effects subside. Unsettled to active conditions are expected from 23-24 Jul due to a possible glancing blow from the 19 Jul CME followed in close succession by a recurrent positive polarity HSS. Quiet conditions are expected to prevail from 25-30 Jul. Unsettled to active conditions are expected from 31 Jul-02 Aug due to a recurrent negative polarity CH HSS, with minor storms likely on 01 Aug when the HSS is at its peak strength. Mostly quiet conditions are expected to return from 03-05 Aug. Minor storm conditions are likely from 06-07 Aug due to another recurrent positive polarity HSS, followed by a steady decrease to active and then unsettled conditions from 08-10 Aug as effects wane. Mostly quiet conditions are expected for the remainder of the forecast period.

Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/

Live Aurora mapping is at http://aurora.sunspotwatch.com/

If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx

Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!

Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g

We’re on Facebook: http://NW7US.us/swhfr

Well, thankfully, this is not happening during this contest weekend: one of the largest sunspot regions during this Sunspot Cycle 24, and one of the biggest in several decades, gave us quite a show, back in October 2014.

Five major X-class (very strong) and a number of moderate and “mild” solar x-ray flares erupted from a single sunspot region – this video covers the time period of October 19-27, 2014, as captured by NASA’s SDO spacecraft. This is from what has been one of the biggest sunspot regions in a number of decades.

Between October 19 and October 27, 2014, a particularly large active region on the Sun dispatched many intense x-ray flares. This region, labeled by NOAA as Active Region (AR) number 12192 (or, simply, NOAA AR 12192, and shortened as AR 2192), is the largest in 24 years (at that point in Solar Cycle 24).

The various video segments track this sunspot region during this period (Oct. 19 – Oct.27, 2014), during which we can see the intense explosions. There are five X-class flares during this time, and NASA’s Solar Dynamics Observatory (SDO), which watches the sun constantly, captured these images of the event.

Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth’s atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel.

When referring to these intense solar eruptions, the letter part of the classification, ‘X’, means, ‘X-class’. This denotes the most intense flares, while the number, after the classification letter, provides more information about its strength. For example, an X2 is twice as intense as an X1, an X3 is three times as intense, and so forth.

Solar Images Credit: NASA’s Goddard Space Flight Center & SDO

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