Fwd: [QRP-L] Friday's X2 solar flare (long)

-------- Original Message --------
Subject: [QRP-L] Friday's X2 solar flare (long)
Date: Sat, 28 Jan 2012 00:41:13 -0700
From: Paul Harden NA5N <[hidden email]>
To: <[hidden email]>



Gang,
I've gotten a few emails wondering why I haven't commented on the recent
solar activity like I did during the last solar maximum.  I mean didn't
it take like 10 years to get through the solar minimum?  Anyway,
laziness, I guess is my excuse.  And I realize we have many new hams who
are learning how propagation works on the HF bands, now that the solar
flux is above like 65 :-( and of course what all this solar flare, CME,
geomagnetic storm stuff is all about.

So here goes.

Friday, there was a fairly large X2 (X1.7 to be exact) solar flare on 27
January at 1837Z.  An X-class flare is the highest category and can
cause radiation storms on earth and effect HF propagation - some of it
good.
Go here to see the x-ray emissions from this flare:
http://www.swpc.noaa.gov/today.html
The first chart is the x-ray emissions as detected by two different
sensors on the GOES-15 satellite.  The X-class flare is easily seen
towards the end of the UTC day on 27 Jan.  X-rays are ionizing
radiation, that is, they can knock electrons away from their host atoms
and molecules.  In our upper ionosphere, this ionizing radiation knocks
electrons away from oxygen, nitrogen and hydrogen atoms.  These
electrons just roam around in our ionosphere, being knocked around by
the ionizing radiation from the sun.  For this reason, they are called
"free electrons," not currently being associated with a host atom.  The
more free electrons in the ionosphere, the more reflective are the E and
F layers, and the higher the maximum usable frequency (MUF).  During a
solar flare, ionizing radiation increases almost immediately, producing
more free electrons in our ionosphere, making the E and F layers even
more reflective, and often raising the MUF.  This condition quickly
improves HF propagation.

Therefore, for QRPers, solar flares are often a good thing.  From the
time of the flare until local sundown, enhanced HF propagation will be
present.  With higher reflectivity, this means QRP signals get reflected
more efficiently for an environment of working longer skip distances
(and new DX) than normal.  Once the sun goes down ... that is, when the
ionosphere above our heads is no longer illuminated by the sun and
receiving the solar x-rays, the free electrons recombine with their host
atoms, reflectivity and the MUF drops, and we fall back into normal
night time propagation.  The lack of ionizing radiation and free
electrons is why the MUF drops at night, and the higher day time bands
shut down.  During the day, this ionizing radiation penetrates deep into
our ionosphere, causing a layer of free electrons we know as the
D-layer.  Seldom do our signal bounce off this layer, but penetrates
it.  Unfortunately, the electron density of the D-layer does eat up
(attenuates) some of our signal.  At night, solar radiation and ionizing
radiation is gone.  The E and F layers combine, and with no deep
penetrating radiation, the D-layer disappears.  Without the attenuation
of the D-layer, this is why signals appear stronger and less noisy at
night - because they are!

As stated above, a solar flare is often a good thing from the time of
the flare until local sundown ... except in those cases of a very strong
solar flare.  Its radiation can be so strong that the D-layer becomes
nearly saturated with free electrons, such that signals can not pass
through at all.   Higher above our heads, the E and F layers are also
saturated with free electrons and the MUF drops quickly, sometimes to a
few MHz or less, or below the lowest usable frequency or LUF. This is a
radio blackout.  The D-layer consumes virtually all of your signal
power, and the MUF can fall to below 3 MHz.  This extreme case of a
total radio blackout is fairly rare.

Friday's X-class flare was associated with a CME - a coronal mass
ejection.  As the name implies, a CME is where the flare belched out
copious amounts of solar mass - mostly electrons and protons.  This is
usually an explosive event, forming a shock wave as the CME travels
outward from the sun.  While the x-rays from the sun travel at the speed
of light, reaching the Earth in about 8 minutes, a CME travels much
slower than light speed, reaching the Earth in about 3 days ... if the
flare and the CME is located near the center of the sun.  If the flare
is located near the edges, or limbs, of the sun, the CME will travel
outward into space, but away from the earth.

Today's X-class flare was a doozie.  The shock wave was measured at
1,532 km/sec., about 950 miles per second, and about 3.5 million miles
per hour.  Anything over about 1,000 km/sec. is considered a strong
shock wave and almost guaranteed to trigger a major geomagnetic storm
about three days later - if it hits the earth.

Friday's X-class flare occurred in region 1402, located on the limb of
the sun.  In fact, that region will rotate out of view by tomorrow.
Therefore, this strong shock wave is traveling away from the sun and
away from the earth.  It will not hit us, so it will not trigger a
geomagnetic storm.  If it were to hit the Earth, it would have produced
a severe geomagnetic storm, the type that can even shut down portions of
our power grid and knock satellites out of orbit.  We escaped this one.
Go to:  http://www.spaceweather.com/
The map of the sun on the left shows where the current active regions
are located on the sun.  As you can see, region 1402 is on the extreme
edge of the sun and rotating out of view.  Region 1408 is smack in the
middle of the sun.  Should a flare occur from 1408 in the next couple of
days, that shock wave will hit the earth.  (1408 is a weak, unorganized
region and not likely to produce a major flare at present).  Region 1410
is just now rotating into view and will be towards the center of the sun
in a few more days.  That is the area to watch for it to grow into an
active region capable of producing flares by early next week.

FORECASTS:
NOAA issues a daily summary of solar and geomagnetic activity, and a
forecast for the next three days, located at:
http://www.swpc.noaa.gov/forecast.html

In Section IV "Penticton 10.7 cm Flux" you will see today's solar flux
was 142 and the forecast for the next three days (i.e., the weekend) is
120, 120 and 120.  Why would the solar flux drop from 142 to 120 so
quickly?  Like overnight?  The reason is because Friday's X-class flare
was also characterized as a "Ten Flare."  This means the flare was so
strong, it affected the solar flux as measured at 2880 MHz, or 10.7 cm
(the Ten Flare thing), where the solar flux is measured.  Thus, today's
daily solar flux was elevated (contaminated) due to the enhanced
ionizing radiation from the flare.  Tomorrow, back to normal solar
radiation and back to the normal solar flux of about 120.  Though, that
is still fairly high for the higher bands to be open during daylight hours.

So if you want to work into areas where your QRP signals don't normally
reach, start keeping an eye on the solar x-ray emissions (at
http://www.swpc.noaa.gov/today.html) for an M- or X-class solar flare.
For the rest of the day, you will most likely experience good signal
propagation with perhaps an opening of the next highest band.  For those
of us who still work, I've noticed the good flares always happen like
2-3 in the afternoon with only moments left in the day by the time I get
home :-(

At the VLA radio telescope, we were observing today at L-band (1-2 GHz)
and S-band (2-3 GHz).  The solar flare did affect observing for about 20
minutes in that the "sky temperature" suddenly increased due to the
flare.  Our switched noise source calibration, which constantly measures
system temperature, detected the sudden rise in sky temperature and
flagged the data so it was not used for science for the duration of the
flare.  The biggest problem at the time is nobody knew what caused a 200
degree K shift in system temperature.  Basically, the electronics system
is always blamed until they realize it was a flare!

Keep an eye on the sun.  Solar activity can be advantageous to QRPers if
you learn a little bit of the physics and learn to read the "tea
leaves."  Don't let the news reports of solar flares scare you off the
bands.

If you have any questions, ask them on the group and I'll answer, or one
of the other seasoned QRPers.

72, Paul NA5N

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[Geoffrey Mackenzie-Kennedy-3]

Kevin, thanks for posting Paul Harden's comment on solar flares.

If you Google Heliotown you will find recordings of the sudden but
relatively short lived increase in background noise as heard on some HF
bands as the result of a solar flare.

During the events which I have heard on 15m, 10m and  6m,  the increased
noise sounded like a pronounced hiss lasting for about 2 - 3 minutes.  Most
events were useful as early warning "wake up calls" to light the amp's
candles!

73,

Geoff
LX2AO






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[Phil Hystad-3]

If you own an iPad or an iPhone the 3DSUN application is FREE and a very
nice solar weather news agency with photos, videos, and other interesting
information.  Just google 3DSUN to learn more about it.

73, phil, K7PEH


On Jan 28, 2012, at 4:28 AM, Geoffrey Mackenzie-Kennedy wrote:

> Kevin, thanks for posting Paul Harden's comment on solar flares.
>
> If you Google Heliotown you will find recordings of the sudden but
> relatively short lived increase in background noise as heard on some HF
> bands as the result of a solar flare.
>
> During the events which I have heard on 15m, 10m and  6m,  the increased
> noise sounded like a pronounced hiss lasting for about 2 - 3 minutes.  Most
> events were useful as early warning "wake up calls" to light the amp's
> candles!
>
> 73,
>
> Geoff
> LX2AO
>
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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[roncasa]

On 1/28/2012 7:28 AM, Geoffrey Mackenzie-Kennedy wrote:
> Kevin, thanks for posting Paul Harden's comment on solar flares.
>
>
>     Most
> events were useful as early warning "wake up calls" to light the amp's
> candles!
>
>


actually, when the band opens, you do not need a "amp".

72
Ron, wb1hga
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[Dave KQ3T]

3D Sun is also available on Android Market.

73
Dave KQ3T

On 1/28/2012 11:19 AM, Phil Hystad wrote:
> If you own an iPad or an iPhone the 3DSUN application is FREE and a very
> nice solar weather news agency with photos, videos, and other interesting
> information.  Just google 3DSUN to learn more about it.
>
> 73, phil, K7PEH
>
>

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[Mike Morrow-3]

> If you own an iPad or an iPhone the 3DSUN application is FREE...

And for those who aren't followers of the Apple religion, the
Android version is "3D Sun".

These apps are from NASA Heliophysics.  They should be free since
your tax dollars paid for them.

But they won't predict the second coming of Steve Jobs yet.  It's
likely that the Android versions never will. :-)

73,
Mike / KK5F

 
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