[karc] [W4VA FARA] X5 flare 6Mar 1730MST

From: George <gsansom@xxxxxxxxxxxx> (by way of Steve Cutway <ve3kc@xxxxxxxxx>)
To: karc@xxxxxxxxxxxxx
Date: Wed, 07 Mar 2012 15:24:57 -0500
ALERT: Type II Radio Emission
Begin Time: 2012 Mar 07 0017 UTC
Estimated Velocity: 2273 km/s
Our current solar wind is 374 km/sec, not much above the static (minimum)
solar wind.  The above NOAA Type II radio alert means the CME resulting from
this flare, escaping the sun, produced type II radio sweeps, which is used
to measure the velocity of the CME as it punches through the sun's magnetic
field lines.
In this case, a whomping 2273 km/sec., or a little over half-million miles
per hour. This shock wave will lose some speed on it's way to earth, but
will still be a significant "blast" of solar wind when it arrives compared
to the present
374 km/sec.
The X5 solar flare came from region 1429, which is approaching the center of
the sun.  Therefore, we won't get a direct hit from this approaching shock
wave, but we'll likely get far more than a "glancing blow."  This, of
course, can produce a major geomagnetic storm when it arrives in about 3
days.
Region 1429 is a very active region with strong and organized magnetic field
lines.  If it continues to grow in size, it could produce more M and X class
flares over the next few days.  And as others have noted, a few flares here
and there always raises the daily solar flux.  I'd keep an eye on solar
activity on the following NOAA website:
http://www.swpc.noaa.gov/**today.html <http://www.swpc.noaa.gov/today.html>
Top chart shows the solar x-ray flux.  You can see the X5 flare right at the
beginning of Mar. 7 UTC.
The second chart shows the proton flux (currently elevated, though not due
to the flare) and the K-index.  Currently, the K-index is <4 (green bars)
meaning a quiet geomagnetic field.  When the shockwave arrives, the K-index
will quickly change to storm status, yellow or red bars.  HF propagation is
usually highly degraded (and noisy) during a geomagnetic storm, which lasts
in the orders of several hours.
General rule of thumb (not exact science):
There will be a radiation storm following an M or X class flare on the
sunlit side of the planet.  This will cause QRN on HF for a few tens of
minutes after the flare.
Once the short-lived radiation storm ends, this radiation also ionized our
ionosphere and the E and F layers for enhanced propagation and raising the
MUF into the higher bands (15 and 10M).  Therefore, shortly after a major
flare to local sundown, enhanced HF propagation becomes very conducive to
QRP signals.
About 3 days later, if the shock wave hits Earth, it will likely trigger a
geomagnetic storm that last several hours.  Working HF is difficult for the
duration of the geomagnetic storm.
Keep an eye on ol' sol.  She's waking up, but who knows for how long.
72, Paul NA5N


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[karc] [W4VA FARA] X5 flare 6Mar 1730MST

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