[qrp-canada] FW: [QRP-L] More Solar Flares and GM Storms

[rattray]

-----Original Message-----
From: qrp-l-bounces at mailman.qth.net [mailto:qrp-l-bounces at mailman.qth.net]
On Behalf Of na5n at zianet.com
Sent: Wednesday, December 06, 2006 4:39 PM
To: GQRP at yahoogroups.com
Cc: 'qrp-l - qth.net'
Subject: [QRP-L] More Solar Flares and GM Storms


Gang,
Yesterday, the sun produced an X9 solar flare, *very* unusual for being near

the bottom of the solar minimum.  Today (6Dec) the sun produced another X6 
flare.  This certainly suggests that active region #0930 will be bringing us

plenty of entertainment over the next two weeks as it rotates across the 
surface of the sun. 

For the *duration* of the flare events, HF can be disrupted by bursty and 
continuum noise, plus enhanced D-layer ionization absorbing signals, if not 
a temporary HF blackout.  However, once that bleeds off in an hour or two, 
the D-layer will be back to normal and the E/F layers will remain ionized 
above normal for the rest of your local daytime hours.  This of course makes

the E/F layers more reflective and raises the MUF.  Therefore, a good time 
for QRPers to check the bands is an hour or so after a large flare until 
local sundown for enhanced HF propagation. 

Most of today we've also been in a major geomagnetic storm.  Believe it or 
not, it has nothing to do with yesterday's X9 (or today's X6) flare.  The 
Earth has simply run in to a high speed electron stream from a coronal hole.

This has exerted pressure against our magnetic field, compressing it, and 
generating huge electrical currents causing high HF noise levels.  This will

subside by later in the day. 

If the sun produces M or X class flares over the next few days, the coronal 
mass ejection (CME) will begin to be pointed towards earth, meaning we can 
expect a geomagnetic storm about two days following the flare event.  The 
closer the solar flare is to the center of the sun, more the direct of a hit

we'll receive on earth.  Today's X6, being near the limb of the sun, will 
probably give the earth only a glancing blow for a few hours of unsettled 
conditions late friday. 

The >10MeV proton count is high.  These protons tend to accumulate in the 
polar regions (where the Earth's magnetic field is weakest).  This causes a 
Polar Cap Absorption Event, meaning high absorption to HF signals for those 
above 45-50 degrees latitude.  These same protons are what fuels auroral 
displays.  Those in the higher latitudes are experiencing aurora now. 

The moral of the story for QRPers:
1) Don't let reports of solar flares, geomagnetic storms, CME's keep you
  off the bands.  Much of this is of short term duration.
2) Enhanced HF propagation, including sporaidic openings on 15, 10 and even
  6M can occur after a major flare for the rest of the day until sundown.
3) This includes possible north-south dx propagation at sundown due to
  gray-line propagation.  (If you do work McMurdo Sound, you better make
  the QSO a snappy one, though -hi). 

Good luck and have fun on the bands.  It's not nearly as bad as it appears.

In fact, it really works in the QRPers favor. 

72, Paul NA5N 


______________________________________________________________
QRP-L mailing list
Home: http://mailman.qth.net/mailman/listinfo/qrp-l
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:QRP-L at mailman.qth.net