CK9, it depends on how you look at it. The initial energy cost in starting the tokamak is greater than the energy it produces, but once the reactor is powered up it sustains itself. think about it like pushing a car up a hill. when you start pushing the car at the base of a hill and get it to the top, youre very tired. but when you push the car and it coasts down the hill, you always come to a stop farther from the hill than you started. there would be an energy price tag to pay to get the reactor started, but once going (and suitably maintained) the reactor would provide more energy over a longer period of time. The main problem with current tokamaks is that superconductive materials have to be super-cooled and this costs alot in refrigeration or in terms of the energy that goes into refining chemical coolants. Current designs would be very efficient if they were actually built how theyre supposed to be. the only 2 tokamaks in existance use inferior superconductors in place of ones that do not exist as of yet. i do know that much interest has been put into carbon nanotube superconductors, but i dont know how far along this is. i stopped looking up info on tokamaks a couple years ago.
also, the question of if you can turn a sphere inside out is really asking: Can you turn a sphere inside out without flattening any curve into a sharp edge? in otherwords, can you do it without folding the sphere? the question is mathematical and not realistic. if you look at the question realistically, the answer changes. this is why i asked the question.
A persons perspective and manner of thinking determines the answer.
Mathematically, yes, a sphere can be turned inside out. realistically it cannot and is impossible within the constraints of the question.
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