About a week ago Wolf DF2PY posted a message here commenting on the recent
adverse levels of geomagnetic field activity and how it will now change for
the good - giving us good 160m propagation.
We'll certainly see less geomagnetic field activity as we move into winter,
but there's another issue we should be aware of. The Sun's magnetic field
is weakening - probably to the lowest levels in our lifetime. With a weak
solar magnetic field, more galactic cosmic rays will be able to get into
the Earth's atmosphere. We are now seeing unprecedented high neutron counts
(neutrons are one of the by-products of cosmic rays)
Since galactic cosmic rays are mostly *very energetic* protons, they can
get down to low atmospheric altitudes, causing collisional ionization in
the D region (and lower E region). A cursory estimate using cosmic ray
ionization rates confirms more ionization in the lower atmosphere. 160m is
not very tolerant of more absorption, so we may see an adverse effect of
the weakened solar magnetic field.
Many of us think that "solar min is solar min is solar min". But maybe a
solar minimum can be too deep for 160m. A good question to ask in the early
2020s will be "how was 160m?" So stay active on 160m and let's see what
happens.
Carl K9LA
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