A 3-5 orders increase of synthetic cosmic rays over background levels? Am I missing something? Even if technically feasible, what about impact on life on earth? Birds, airliners, marine life... Phytoplanktons emit dimethyl sulfide (DMS) which eventually leads to aerosol formation and cloud cover. The CLAW hypothesis postulates this as part of planetary homeostasis. So what would a 3-5 orders increase of cosmic rays do to phytoplanktons, and the natural cloud coverage they enable? And to the oxygen that phytoplanktons provide us with? Even if shooting from below, what's the fate of millions of balloons in the atmosphere? What goes up must come down... And the footprint of millions of jets? Again, danger to birds and airliners? Maggie On Monday, August 20, 2018, 11:23:19 AM GMT+2, Andrew Lockley <[email protected]> wrote: Thanks for your question, Oliver. The reason to use a space based system is similar to the approach for earth observation satellites - even coverage. A satellite in GS orbit can 'see' roughly a third to a half of the world. Because the atmosphere is thin, compared to the size of the earth, most beam attenuation is likely to occur in the troposphere, where 75pc of the air is. That means a satellite mounted system would only have to penetrate a few kms of thick atmosphere, at most. Crudely, I'm assuming beam range and power scale together. A kW system gives you kms, MW gives you thousands of kms. (I said GW in an earlier email, which would be the case if you relied on lossy accelerators for high particle energy, not high density, as Russell helpfully pointed out.) By contrast, a ground-mounted system would have to work over distances 3-4 orders greater. A ship-based system would be technically viable, but its slow speed would inhibit its coverage, quickly reaching local saturation - unless you used a high energy beam to reach 1000kms or so. A high-energy system would need to be mounted on a ship the scale of an aircraft carrier (which has a similar power output to a 747, although much more available as electricity). A jet or balloon system would be plausible, but would have a beam range of perhaps ten of kms (balloons) to hundreds of kms (large jets), necessitating potentially millions of platforms to provide global coverage. I'm neither a satellite engineer, nor a cosmic ray expert - so multi-order errors are inevitable in my reasoning. Andrew Lockley On Mon, 20 Aug 2018, 09:29 Olivier Boucher, <[email protected]> wrote:
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, <[email protected]> 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 -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- BAMS State of the Climate 2017 has an aerosol section in the Global Climate chapter -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. 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