Mike, you're right. It's protons or hydrogen ions in the large mass
ejections.
There are some photons both ionizing (x-rays and gamma rays) and visible,
but mostly hydrogen ions.
Gary K5AMH
On 1/5/2024 11:15 AM, Mike Knerr via BVARC wrote:
I understood that a coronal mass ejection released protons, not
photons. These also bring high electromagnetic fields with them.
I understood the electromagnetic fields are causing the problems.
Just a thought.
Mike Knerr KI5UBL
73
On Fri, Jan 5, 2024, 10:03 AM Stephen Flowers via BVARC
<bvarc@bvarc.org> wrote:
Richard,
Good morning and Good question. The way I understand it, solar
flares emit a large amount of photons at various frequencies. If
these photons are sufficiently energetic, then they will pass a
large portion of the ionosphere and impact what we refer to as the
D layer. Note that the D layer is a daytime ionospheric layer
that according to some models in the literature is made up of NO^+
, NO^+ (H_2 O)_n , H^+ (H_2 O)_n , CO_3 ^− , and O_3 ^−
These species readily combine with free electrons that increase in
numbers due to the flares. This in turn results in “less
refraction" of E&M waves that we as amateurs need to bounce our
signals off of to communicate. In a nutshell, D layer
constituents don’t refract as much and this is interpreted as “D
layer absorption”. If you look at this
<https://www.swpc.noaa.gov/products/d-region-absorption-predictions-d-rap>
URL
you can playback a movie of the latest D layer absorption
measurements. During a solar storm you’ll see the bar graph in
the right hand corner increases across multiple frequencies.
Note that in a solar flare event the lower frequencies are
*/preferentially/* impacted.
Screenshot 2024-01-05 at 9.48.35 AM.png
Of course other layers in the ionosphere are also affected by
solar flares in ˜8 minutes of emission and CMEs hit us w/a delayed
impact of ˜1 day or so; however, you may be on to something when
you say that the lower frequencies suffer a bigger impact. In
that case, you may be right in that the higher frequencies, 20m
and higher, may be the way to go for Ham radio ops during solar
storms.
Thank you for bringing up this topic!
73,
Stephen (W2WF)
On Jan 5, 2024, at 9:03 AM, David Holden via BVARC
<bvarc@bvarc.org> wrote:
A strong solar storm can cause a complete blackout of HF
communication including the higher frequency bands. I was in a
QSO a year or so ago and it just dropped as a solar storm hit.
The noise floor dropped to zero as not even noise could propagate
through the highly energized atmosphere.
Lesser solar storms can increase noise particularly on the lower
bands so 80 might be unusable while 20 might just be noisy.
David WJ9O
On Jan 4, 2024, at 10:25 PM, Richard Bonica via BVARC
<bvarc@bvarc.org> wrote:
To all,
Tell me if I am wrong on this. During these solar storms, it is
my understanding to use the higher frequency rather than lower?
If so, is 20 and 40m bands a good choice?
Thank you in advance
Richard
KG5YCU
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--
Gary Sitton, K5AMH
gasit...@comcast.net
SDR/DSP Consultant,
"Have FFTs, Will Travel."
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