[K6BW] Solar Flare Today - Report from QRP-L

[Bill Smith]

Gang,
Today's X9 flare was indeed quite a surprise, not only to us hams, but to
the scientific community as well.  The flare occurred right on the east limb
of the sun, that is, just coming into view, such that the active region that
produced it has not yet been viewed.  This region will be rotating into view
over the next day, and over the next two weeks will move across the surface
of the sun (from east to west, or left to right on most solar images).

Since this flare was on the east limb, Earth will experience on the
speed-of-light emissions (ionizing radiation and the radio storms) - NOT a
subsequent severe major geomagnetic storm.  Although, NOAA has predicted an
A=20 (minor storm) for Thursday, anticipating a glancing blow from the
shockwave.  It will not be a direct hit.  However, over the next week and a
half, further solar flares from region 0929/0930, as it nears the center of
the sun, could cause major geomagnetic disturbances on Earth.

I talked to our head solar astronomer, Dr. Tim Bastian, who said the 40-ft.
and 300-ft. antennas at Green Bank, WVa are now mapping this area of the
sun, trying to get some spatial resolution to see what this area looks like
 - difficult when it is right on the limb.  Additionally, there are some
pretty images of the Type II and Type IV sweeps on their radiometer.

He has given me permission to pass on the following information.  This is
his website of the Green Bank solar radio burst spectrometer (GBSRBS), which
is a newly created and EXPERIMENTAL website you might find interesting,
though it has not been announced/released for public use yet (but released
to QRP-L by permission).  It is at:
http://gbsrbs.nrao.edu

Click on SELECTED EVENTS, then Type II and Type IV.
Type II sweeps are caused by the shockwave of the flare punching through the
magnetic field lines of the disturbance.  They "sweep" from higher
frequencies (50-300MHz) to lower frequencies (5-20MHz, depending on the
intensity of the shockwave).  On earth, they will sound like bursts of
static flying through your passband, much like ignition noise.

This X9 has been producing Type II events.

Type IV sweeps are more continuum noise generated by the solar flare, though
bounded in frequency to the 10-100MHz or so range, though effects much
higher are not uncommon for a large flare.  On earth, the Type IV sweeps
causes an overall increase in the HF noise level.

This X9 has been producing Type IV events.

Now go to the DAILY SUMMARIES, click on DEC (December) and 2006.
Click on Dec. 05 under the "BI 12-62 MHz" column.  This is the Bruny Island
Radio Spectrometer in Tasmania, which shows today's events so far.  Can you
see the Type II sweeps (going from the high to lower frequencies)? And, the
Type IV continuum noise?

The NRAO radio burst spectrometer is also real time, however, it is not
updated on this PUBLIC website until the end of the UTC day, so Dec.05 is a
bit blank yet.  However, look at it later, which will give you a real-time
(at least at the time -hi) spectrum of what happened to the HF bands down to
12MHz.  You can compare it to Dec.04 (yesterday), which is pretty boring.

Again, this will soon be an official NRAO (National Radio Astronomy
Observatory) public website, and soon to have the daily real-time
spectrograph on it, but still under development.  Dr. Bastian was kind
enough to allow me to share it with those hams so interested.

Lastly, Dr. Bastian is also observing, etc. to determine the effects of this
flare to our upper ionosphere, and interested to know what effects this is
or has had on HF propagation.  There are facilities that measure these
things, but it will be at the end of the UTC day or later before their data
is released.  I am at work and no access to any HF gear.  So, for those of
you who have been on the bands since this morning, let me know (either
private or via QRP-L) if you heard any Type II sweeps (the bursty, ignition
noise stuff and approx. what time and frequency), an overall increase in
noise (type IV), or if you experienced an HF black-out or near blackout
condition.  State your approx. location.

It is hard for some of these astronomers to realize there is a fleet of
people out there who are experiencing these things real-time on ham radio.
A sampling of reports across the country of noted effects could be helpful
right now (as some of the propagation study instruments are shut down during
the solar minimum).

I'll pass on anything interesting that might result from today's solar
observing we're doing on this.

Thanks and 72,
Paul NA5N

National Radio Astronomy Observatory (NRAO)
Very Large Array (VLA) Radio Telescope
Socorro, New Mexico