Dear Andrew,
as I stated before, I have some doubt about observed relationships
between cosmic ray and cloudiness and if real, the physics is very
unclear. However I do not understand your post. If there is such an
effect, then why would you want to shot these particles downward from
space rather than upward from the surface. The objective would be to
increase low-level cloudiness, wouldn't it ?
Regards,
Olivier
There appears to be some confusion here in terms of the numbers to
use. Most of the particles are atomic nuclei (overwhelmingly
hydrogen). These are therefore charged, and thus are substantially
attenuated by the earth's magnetic field. I've been unable to
determine the extent, from a quick Google.
Furthermore, a proportion of scattering attenuation occurs in the high
atmosphere, where it's too dry to produce clouds. It may therefore be
more effective to use lower-flying aircraft, which are less lossy by
this mechanism - although they may have very limited beam range.
Nevertheless, Google's project Loon shows that mass production of
non-high altitude balloons is at least worthy of consideration -
numbers can potentially overwhelm range disadvantages.
Finally, there's the issue of energy distribution. I've been unable to
find a source that links particle energy to cloud CCN. The number peak
at 0.3GEv may not be representative of an efficacy peak. Certainly,
highly energetic particles are disproportionately effective, but it's
not clear whether their numerical rarity makes them irrelevant,
overall. There are significant technical issues with producing
high-energy particles in orbit. Individual particles are travelling at
near light speed, and they experience significant relativistic
effects. It therefore requires serious infrastructure to produce them.
That's impractical for a satellite. However, intermediate energy
accelerators could be mounted on 747-type platforms, and full sized
accelerators could be land based. One problem with very high energy
particles is that they're *individually* dangerous. The highest energy
particles have the energy of a baseball travelling at nearly 100kmh.
You can't go shooting those at airliners.
Further thoughts welcome.
Andrew
On Mon, 20 Aug 2018, 01:55 Russell Seitz, <russellse...@gmail.com
<mailto:russellse...@gmail.com>> wrote:
The grid-to-beam efficiency of greater than GEV particle
accelerators ranges from kess than 5 % for high current systems ,
to as little as 0.02% for superconducting colliders like the
LHC. As the global cosmic ray flux is of the order of 5 GW,
matching it might therefore take anywhere from a hundred GW to
several tens of terawatts.
At the high end of that power range one runs into a serious
feedback- the cloud nucleation cooling might be overwhelmed by
extra CO2 radiative forcing from the thermal plants in the grid
powering the accelerators.
On Sunday, August 19, 2018 at 10:17:58 AM UTC-4, Andrew Lockley
wrote:
Cosmic rays cause cloud condensation nuclei. They are
therefore believed to affect cloudiness, and therefore
climate. If we made more cosmic rays, that would likely make
it more cloudy. Whether this was a warming or cooling effect
would depend on whether it was cirrus or cumulus clouds (NB,
sometimes making cirrus ultimately removes water, resulting in
less cirrus)
Cosmic rays are almost all protons, with an typical energy
peak distribution of 0.3GEv. (4.8×10^−11 J). No idea if
that's the right energy for CCN, but we can tweak that later.
Creating artificial cosmic rays is possible, using a linear
particle accelerator. This is similar to an ion thruster, as
used in space probes.
To affect climate, you'd probably have to get densities of the
order of 1/s/sqm (more on that, later).
360 million square kilometers of ocean is 360tn sqm or
3.6x10^14sqm. You don't really want to send particles into
people, and the cleaner air over the oceans makes them more
effective.
A kilo of hydrogen contains 6x10^26 protons.
That means 1kg of H2 gives you enough material for 1.6x10^12s
= roughly 50 years - so a satellite could easily carry enough
material to do the job.
Power is 3.6x10^14 x 4.8x10^-11J/s = 17kW - again, well within
what a satellite could muster (roughly 100sqm of solar panels,
at around 20% panel efficiency (conservative) and 50pc
conversion (made up) efficiency).
Cheap satellites are about $50m - well within the capabilities
of a rich philanthropist. Even if this is not cheap, it's
still only perhaps 500m
If I'm out by 5 orders (1 ray per sq cm, not per sq m each
second), then that's only 10,000 satellites. That's expensive,
but not outlandish. Superficially, that would be $500bn at the
lower cost, but there is likely a 10x or 100x experience curve
cost reduction, meaning the whole programme would be about
$5-50bn max.
As an alternative, you could use aircraft or balloons, but
beam attenuation would be a serious issue. 40km balloons can
be launched, albeit with small payloads. They would fly at the
bottom of the mesosphere, over 99.9pc of the atmosphere. So
maybe beam attenuation would be tolerable, at that height. I
don't know how to calculate it, but I'm guessing it would be
cms to kms - so not really far enough to make a difference to
climate. You could perhaps have mountaintop accelerators with
very high powers, and a sweeping beam (like a lighthouse). If
the power requirement was GW-range, then maybe the beam range
would be a hundred km, or so. That might be enough to work,
but it would have some pretty significant effects on local
atmospheric chemistry - so probably not a good idea.
Any thoughts from anyone?
Andrew Lockley
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BAMS State of the Climate 2017
<https://www.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/state-of-the-climate/>
has an aerosol section in the Global Climate chapter
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