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The K7RA Solar Update


 This week (September 1 to 7) two new sunspot groups emerged on September 1, two more on September 2, one more on September 5, another on September 6 another on September 7 and one more on September 8 when the sunspot number rose to 75, 7 points above the average for the previous seven days.

But average daily sunspot numbers declined from 74.9 to 68, while average daily solar flux rose just two points from 123.8 to 125.8.

On Thursday night the sun is peppered with spots, but none are magnetically complex and solar flux seems listless at 126.6, barely above the average for the previous seven days.

Geomagnetic indicators were way up, average daily planetary A index rose from 10.1 to 24.6, while middle-latitude numbers increased from 9.4 to 17.4.

September 4 was the most active day when planetary A index was 64. On that day the college A index in Fairbanks, Alaska was 91.

Predicted solar flux is 125 on September 9 to 13, 120 on September 14, 115 on September 15 and 16, then 125, 126 and 120 on September 17 to 19, 125 on September 20 and 21, 115 on September 22 to 24, 120 on September 25 to 28, 118 on September 29 and 30, 115 and 125 on October 1 and 2, 120 on October 3 and 4, 122 on October 5, 120 on October 6 and 7, 125 on October 8 to 11, 126 on October 12, 125 on October 13 and 14, and 126 on October 15.

Predicted planetary A index is 50 on October 1.  Otherwise,  8 on September 9 to 11, 5 on September 12, 20 on September 13 and 14, 15 on September 15, 8 on September 16 and 17, 5 on September 18 to 22, then 12 and 10 on September 23 and 24, 14 on September 25 to 27, 8 on September 28 and 29, then 22, 50, 25, 16, 12 and 10 on September 30 through October 5, 8 on October 6 to 8, then 5, 12, 15 and 10 on October 9 to 12, 8 on October 13 and 14, and 5 on October 15 to 19.

OK1HH writes:

"Over the past seven days, a large coronal hole moved from the central meridian to the western limb of the solar disk.  Its position relatively close to sunspot group AR3089 meant a high probability of a geomagnetic disturbance in the following days, since September 4.  Its onset as early as 3 September (class G1) was related to the intensification of the solar wind and the opening of a rift in the Earth's magnetic field.  The solar wind flow from the large coronal hole finally hit Earth's magnetic field on September 4 and triggered a G2 class geomagnetic storm.

At the same time, two sunspot groups so large that they affected the Sun's vibrations developed on the far side of the Sun.  These were AR3088, which had last left the Sun a week earlier and was the source of a large CME heading for Venus on September 5.

On September 7, AR3092 crossed the central meridian and had a really long tail above the surface of the Sun.  It was a filament coming out of the core of the spot and curling up into the solar atmosphere.  Inside the filament was a long tube of relatively cool, dark plasma.

Thereafter the Sun was relatively quiet.  The solar disk was dotted by sunspots, but these have a stable magnetic field, so the chance of flares was low.

Earth's magnetic field was mostly disturbed on the 3rd to the 6th. Thereafter was unsettled to active on the remaining days.  Shortwave propagation was below average, worst at the end of the disturbance on September 6.  An increase in f0F2 occurred at the beginning of the disturbance on September 4.

Now a few quiet days followed by another disturbance on 13 and 14 September is expected."

I (K7RA) have been seeing more strange 12 meter propagation recently.  Over and over for several days using FT8 as a propagation test tool with, I would call CQ and see that only stations in Florida were receiving my signal.  It looks very odd on the map.  Florida does have a very large ham population, but this just seems so peculiar.

Regarding the recent overloading of the sensors at Penticton, I noted I had seen this before, but didn't realize how rare it was.  I paged back through the DRAO archives, and unless I missed something, the last one was in 2015 on June 22 when the 2000 UTC flux reading was 246.9.  The noon solar flux the following day was only 116.1.

Tamitha Skov's report is a week old, but too late for last week's bulletin:

Two massive sunspots:

Longtime contributor David Moore sent this:

Big explosion:

Our angry sun:

So huge:

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Sunspot numbers for September 1 through 7, 2022 were 67, 71, 68, 62, 79, 56, and 73, with a mean of 68. 10.7 cm flux was 116.3, 129.8, 123.4, 128.3, 130.2, 126.2, and 126.1, with a mean of 125.8. Estimated planetary A indices were 9, 8, 25, 64, 32, 20, and 14, with a mean of 24.6.  Middle latitude A index was 9, 10, 23, 33, 21, 14, and 12, with a mean of 17.4.



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