DeltaV wrote:How about a fusion centrifuge (my washing machine was just spinning up)? You'd have an outer layer of heavier B11 and an inner layer of lighter H nuclei. Then apply a radial E field for fusion. I'm only half joking. The tangential velocity needed would probably be a sizeable fraction of c.
Excellent idea! Outstanding!
Well, I would say that, wouldn't I... because that's kinda what I'm building.
I would call the principle "electro-centripetal magnetic" ion confinement, were I to add it to my own list.
The only issue is that my list is strictly those ideas taken through to published experimentation.
So, in point of fact, there are actually several patents already covering this idea in different ways, it's just that no-one's built one yet. My list had to cover only experimental works, because the total number of hair-brained fusion ideas I could list that have appeared in patents would multiply that list by a few times. I am planning on such a list one day, but bigger fish to fry right now...
On to your technical observation - it seems to be a misconception people have that you need ions to go as fast as possible to make the best fusion. This is erroneous. Once you get collisions in the MeV range you end up with Oppenheimer-Phillips stripping of the nucleus (the whole thing just falls apart) and you get a mass of neutrons and 'bits-of-old-nucleus' and it is all very endothermic. In fact, early ["professional" (read:institutionalised!)] observers of fusors commented that the neutrons observed weren't fusion neutrons but were 'just' O-P neutron products. They were wrong on this, of course.
However, clearly, too low and you get no chance of fusion. Fusion is one of those 'on the fence' kinda probabilistic processes for which there is a surprisingly tiny window of opportunity.
(If you get to consider all the facts, it rather looks like someone has made the whole of physics in this way rather intentionally just as an intellectual puzzle. I don't believe in there being a sentient 'God', but if someone were to try to persuade me by revisiting all the odd 'windows of opportunity' in physics that mean the universe a reality, like the fine structure constant and the molecular basis for life itself, then they could take me pretty close!! This work isn't a vocation or even a hobby for me, it is a frustrating, beguiling puzzle because I can see the window of possibility is soooo small it seems impossibly unlikely that it is not "an intentional" puzzle for which there is a solution planned!)
Anyhows... on the subject of how fast ions need to go for fusion - the range is quite small - the minimum collision velocity is around the 1Mm/s, which is for deuterium at 10keV, and the highest is around 10Mm/s for proton-based fusions at the 600keV range. So 'velocity' is spread only within a single order of magnitude for fusion, and represents no more than a table-top sized device operating at 1 to 5MHz rotation. Seems like it would be a very useful option, to me, even if it turns out not to be 'the best' or 'most powerful' of several future solutions to fusion.