DaveMart
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DaveMartParticipantThanks all.
One thing I like about Focus fusion is that they are upfront about the difficulties.assymetric implosion:
Thanks. Even I can understand that.
Concerns about black body losses are limited because it ain’t a black body!
I like it!DaveMartParticipant@Joe:
I am currently still taking lessons from my cat on the physics of fusion, and my cat is pretty rushed and so has not got time to properly tutor me.
What I am doing is simply passing on others comments.
My understanding had previously been pretty much as you outline, but naturally for guys like Cyril more in depth analysis is required.
Hopefully this one will pan out!DaveMartParticipantIt sprawled across two sites:
http://nextbigfuture.com/2012/08/lawrenceville-plasma-physics-raising.html
And:
http://www.energyfromthorium.com/forum/viewtopic.php?f=2&t=3762&p=47147#p47147I am trying to move the discussion here, and will post on those sites to that effect, but pstudier has now replied to Cyril on the thorium energy site:
‘Good points! Conventional fusion people generally assume that all the energy that escapes the plasma is adsorbed. So all these gradients, plus complex interactions between plasma and magnetic fields lead to instabilities. Conventional fusion people have been building tokamaks bigger and bigger for decades, and with each new size, they get hotter, denser plasmas and new instabilities. The Wikipedia article “Plasma stability” lists over 50 different types of instability. These novel fusion schemes, focus, polywell, etc, are orders of magnitudes from breakeven and have not even begun to start evaluating the instabilities. For example, the polywell people brag about detecting 3 neutrons.
There are good scaling arguments that say tokamaks will never be economical, based on the maximum power density allowed by radiation damage of the first wall, costs of the magnets, blanket, shielding, support structure, etc.
Fusion is easy, breakeven is horrendous, and economic is probably impossible.’
And sebtal to pstudier on NBF:
‘The flip side is you really don’t want heavy elements into your plasma (this is why fusion is so damned hard), because while fully ionizing low elements is viable, if you introduce iron etc. atoms, they don’t fully ionise, and the resultant line emission leads to radiative quench of the plasma.
One of the problems with MCF is that eventually,a magnetic surface intersects the wall, and heavy elements are introduced. One of the significant advances in the field was the invention of divertors and x-points so you could peel off a flux surface using a magnetic null point (this sounds really complicated in words: it’s just this http://www.google.com/imgres?u…, and have the plasma directed onto a material surface in a controlled way at a much greater distance (along the field line) from the core plasma preventing contamination.’
DaveMartParticipantThat would be the Bussrd engine – there is a video on Google
Here is a link to the article :
http://www.ibiblio.org/lunar/school/InterStellar/Explorer_Class/Bussard_Fusion_systems.HTML
I don’t think it is designed for take off from a planetary surface, so far as I remember.DaveMartParticipantDemeter Design, Cara wrote: I may just be sceptical but if countries aren’t allowed to do nuclear research (and I am NOT in support of weapons manufacturing) than how would nuclear energy be universally available (which is in the focus fusion forum. There is such a fine line between nuclear energy and nuclear weapons wouldn’t it be better to leave it alone altogether otherwise people end up fighting about who has the right to use the energy. The second part of this comment refers again to the motto (which I don’t have in front of me so this isn’t verbatim.) There is no unlimited energy source as the maintenance of such a system requires man hours, materials, etc. all of which is finite. Wouldn’t the more practical solution be to reduce energy consumption and focus on solar, wind, and microhydro which all have much less risk associated with production? Although nuclear energy has some uses such as space travel, it just seems that there are much easier ways to obtain energy, especially when you make buildings and machines more efficient.
Wind and solar resources are not then, by your account, unlimited as both require man hours, materials etc – in the case of wind resources at least, massive amounts of it for an unreliable resource.
Your broadbrush characterisation of the risks of nuclear as oppoised to the other resources you mention also seems to take little account of the different risk profiles of different methods of producing nuclear energy – one of, although not the only one of, these being focus fusion.
As for energy conservation being some sort of solution to energy requirements, if one were only concerned with the developed world that might just about wash, but vast numbers of people in India, China and throughout the developing world can’t have a reasonable standard of living on their present energy use, regardless of how economical they are with it.
Essentially there is no technological challenge to producing all the energy the world needs, if need be without increasing CO2, as it could be done with coal technology and sequestration, for a total bill of perhaps 20% on energy costs – far cheaper then restricting economic growth or going to crazy levels with ultra-expensive solar power solutions.
That is not to say that a much more elegant solution such as Focus fusion would not bring great benefits, not least for the huge numbers of miners who die annually.DaveMartParticipantI would have thought the economics of using mines would be horrendous. As others have said you would firstly need to sel the surfaces to prevent contamination by heavy metals and so on, and that then brings you to the main problem – the weight of all that earth and rock overhead.
It costs a lot of money to maintain mines in that high pressure environment – the greatest difficulty would probably be for the aquaculture idea, as it would then be very difficult to detect leaks bringing in contaminents.
In an environment where you were growing trees etc then you would need to maintain the pumping operations to limit water ingress.
All of it could be done, but why?
There is no shortage of waste land – all that you normally have to do is add water. Cheap power would make it easy to do that, without any of the costs and difficulties of the approach you suggest.
If for some reason you wanted to minimise land use, the productivity attained by hydroponic or systems where the roots are suspended in air is massive – you basically would have a series of containers, easily accesible at ground level.
Given reasonably cheap power, there would be little difficulty in getting enormous productivity form such a system.
If for some reason you wanted to economise even more on land use, rather heavier construction of the containers would allow the roofing over and planting to grass of the entire production area – still one heck of a lot cheaper and easier than keeping open a deep mine.
Sorry, it doesn’t sound like a flyer to me.
Regards,
DaveMartDaveMartParticipantVery interesting – and am I right in thinking that this could be tested on a small scale by hobbyists?
Presumably though, you would need to reach a fair size before it would serve any useful function as an energy store, which would seem to me to be the easiest early application.
Anyone like to hazard a guess of how big you would have to build to get something useful?
Or could you build very lightweight mobile phone masts using this technology, a few tens of meteres tall?
Regards,
DaveMartDaveMartParticipantDuke Leto wrote: That’s about what I thought in terms of biomass needs.
That’s why I figured direct synthesis of hydrocarbons from water and CO2 would be simpler, less steps involved and easier access to cheap raw materials. Of course I don’t know if there’s a direct synthesis method other then photosynthesis for sugar and then on through your method.
What about cultivating dense algae in artificially lighted tanks year round for biomass?
Algae growth:
Seems like it might be the way yo go to me – I agree with other comments that a lot of the stuff about fuels from other plants is pretty much a plan to mine the tax-payer – but algae cultivation can grow fuel at sufficient densitiies to make a real contribution to energy needs – the initial capital costs would be high though.
http://news.com.com/Want+alternative+energy+Try+pond+scum/2100-11386_3-6145197.html?tag=nefd.lede
Regards,
DaveMartDaveMartParticipantThe Bussard system is more limited than DPF. It
DaveMartParticipantHere is the transcript of the lecture by Bussard:
http://www.askmar.com/ConferenceNotes/2006-9%20IAC%20Paper.pdf
There is discussion of it on the forums here:
http://fusor.net/board/index.php?site=fusor&bn=
Apparently Bussard has provided sufficient technical info so that others may readdily copy his work.
You also do not necessarily need to use a steam generator to get power from it:
http://www.ibiblio.org/lunar/school/InterStellar/Explorer_Class/Bussard_Fusion_systems.HTML
I am very interested in the evaluations of the technically able members of this forum – it’s all magic to me! 😉
Regards,
DaveMartDaveMartParticipantYeah, the actual reactor is 2.5-3 meters across:
http://www.google.com/search?num=100&hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=bussard+fusion&spell=1
The good news seems to me to be that as soon as someone decides to put money into either focus fusion, or the bussard process, then a lot of other people are going to start thinking that perhaps they should try the alternative – so IMHO this actually increases the chance of raising funding for focus fusion – another opportunity to break the funding logjam.
Regards,
DaveMartDaveMartParticipantI probably misunderstood, but I thought that Bussard was saying on the video that the actual reaction vessel was only 2.5 meters across – of course the advantages you mention of the direct conversion by a linear accelarator of energy is accurate as against steam conversion, and the ff would have the advantage of being operable at for les than 50MW.
Regards,
DaveMartDaveMartParticipantIt’s a bit much when the American Academy of Sciences says that this is the ‘only’ fusion reactor design which uses boron and doees not emit radiation – they don’t seem sufficiently well-informed to carry out their responsibilities.
Could someone please give me a run-down, which may also help other people without great echnical expertise, of focu fusions advantages over this technology?
Regards,
DaveMartDaveMartParticipantFocus fusion should be hugely switchable – nothing to heat up or cool down, no building up to any critical level, not even any boilers to heat up.
Should be power at the flick of a switch, and so cheap that it would not maake any sense to store energy, save in the form of perhaps hydrogen conversion for use as a fuel.
Regards,
DaveMartDaveMartParticipantAlex Pollard wrote:
And as a way explaining why it gets so little attention, I lead into this by talking about how misguided institutional science can be.
It’s important though to avoid getting grouped with those ideas which would require a radical rethink of physics to be possible – for instance cold fusion.
Without pre-judging or commenting on what is possible in that type of field, focus fusion implies no such challenge to current understandings of physics, and the issues involved are purely ones of technological implementation.
It is also one whcih has also attracted institutional support currently in South America and previously elsewhere, and many other goups are looking at plasma physics, whose potentials are only currently being realised, and may lead to a re-think of older approaches, which attracted considerable funding before some of the more modern and potentially far more financially attractive possibilities were understood, and so a degree of re-assesment of priorities in funding of the 40 year old research into fusion technolgy may be appropriate.
A degree of care in approaching institutional science, with great care to the terms in which those institutions are addresed, might yield dividends.
Regards,
DaveMart -
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