Here is an idea. Take steel ball of 11m radius filled in its core with some Deuterium and Tritium. Cover it all with sound transducers able to generate 10ns pulses with sound power of 1KW per square meter per pulse. Now assume that all this sound energy is going to be directed inward and is going to focus at 50um sphere at the core (50um because this equal to one wave length at sound speed 5100m/s). This may not be quite realistic, but let say for now. The total of 1.52MW pulse once compressed to 50um radius is going to increase energy density 4.8e+10 times. You need 7e+8 pulses like this one in order to increase energy density at the 50um sphere to the level matching temperature of 15keV (174MK). All this is going to cost 2.9KWH of energy and could be done in 13.7s. And voila, fusion power at your disposal. I also conveniently assume that 11m steel ball could withstand fusion pressures (please offer calculations if you can). As to temperature, it is going fall with square of radius and useful heat needs to be extracted through cooling arranged outside. List of problems is long: -energy dissipating well before reaching center -convections abseting symmetry -… I though it is cool, but because it is late, it may have no sense whatsoever, -al
Yeah, it MUST be late! Please Register or Log in to view the hidden image! Without going item by item, I'll simply point out that your assumption the steel ball could withstand fusion is your major problem. One cannot construct ANY material object that can contain nuclear fusion. That's precisely why all the work that's been done has involved magnetic containment.
It all come down to the temperature gradient: the minuscule plasma at the core is going to be supported by cooler plasma around and then each additional layer will have a lower temperature. At some distance from center temperature should fall enough for a solid metal to be able to form, especially if you extract heat. I was more concern about pressure then temperature.
I think Read Only is right... If you are able to generate a fusion reaction, there is no guarantee that it will actually give you any energy (i.e. it may take more energy to start the reaction that the reaction outputs). And if the fusion reaction is to be self-sustaining, I think there is probably some critical density you need of hydrogen/deuterium/tritium. And getting that density would probably be pretty difficult without blowing up your ball. I dunno---I would be interested to see a calculation or something.
I didn't mention temperature at all - it IS the pressure that you can't contain physically. Please Register or Log in to view the hidden image!
Instead of pressure/tempreture lets talk energy density. Nothing can withstand something like 5e+25Wm-2 corresponding 174MK. But if you holding it at a distance of 1e6 times larger, then you need to be able to coupe with 1e12 less power. Which still brings alarming 5e13Wm-2. Did I say it will not fly apart ?
Nope, you did not say it would fly apart - until just now. Please Register or Log in to view the hidden image!
However, if you manage to deliver the 5e13Wm-2 in 1us, you need 5e7Wm-2 to warry about. That roughly 6 times more then a 100W lightbulb (circa). But I see a problem ... initial calculations need to be redone.
yeah, but you need a large density of the gas in the interieor region. Then fusion doesn't happen only in the middle, it happens everywhere. So we're back to the original problem Please Register or Log in to view the hidden image!
Only in the middle. In a tiny,tiny middle and for a small fraction of time: focus energy and then relax and recover heat. It will not happen anywhre else because tempreature will fall down with radius R, as radiation flux I decreases: T ~ I^0.25, I ~ R^-2 => T ~ R^-0.5. One needs to be careful not cause run away conditions to explode a whole things, like a nuclear chain reaction. I believe fusion is esier to control. Just add it to the list of problems.
I think any attempt to develop this thing is hopless. There are too many complications. I give up. The final insights: - the sound energy input pulse pumping can be distributed over longer time, let say many microseconds. As train of pulses converges toward center they will merge into a single shock wave of much shorter duration. This is similiar effect to a wave breaking at the shore. This means that one can expect additional power gain of perhaps few orders of magnitude. - Attempt to create 174MK for 50um sphere to undergo fusion was not necessary. You can lower your temperture let say 10 times and still accomplish fusion because molecular speeds distribution follow e^(-mV^2/2kT).
