Talk-Polywell.org

net 12.7 megajoules per shot.

Hmmm.
That is not that bad indeed, if the calculation is correct.
That still leaves the problem of the 100 km long accelerator and then you still need to breed Tritium.
The things people do for fusion...

nextbigfuture wrote: .....

3.3 megajoules to produce the millimeter diamond and accelerate it
16 megajoules generated
net 12.7 megajoules per shot.

So, a Q of ~ 4.5. After thermal conversion perhaps a net profit of 1.5 to 4 depending on the efficiency of the steam plant and if any use could be found for the waste heat.

Dan Tibbets

Dan, I think that he had already factored in the ineffecient conversion, when he assumed that 80% would be wasted. But maybe I missunderstood that part.

"The peak energy from an impact is 4 petawatts but mostly at 1.5 petawatts over about 40-50 nanoseconds. 80% of the energy is wasted."

I took it to mean 80 % of the energy is wasted in the accelerater and/ or in heating the diamond - target mush to fusion temperatures, or escapes without contributing to the fusion mush energy.

Dan Tibbets

From page 5 -

From these figures, we can see, though 80% of the fusion energy is wasted as almost transparent high energy neutrons, and most of the rest goes to electron and radiation, what remains is still enough to warm up the neighboring ions to fusion temperature, if the incoming bullet is fast enough.

http://mail.phy.pku.edu.cn/~lei/df/hedip.pdf

They only modelled up to 830 km/s
There is a big jump from 800 to 830 km/s

I think it gets better as they go to 1000 km/s.

I may not fully understand their charts.

They model and show the energy that goes to electrons and ions.

It seems about 0.4 PW in the electrons and ions for the 40 nanoseconds.
16 megajoules.
so convert off of what efficiency can be converted from electrons and ions.

Probably need to go faster to get really good efficiencies.

As a trivial aside:
One interesting thing is that if you had a future spaceship. You could fly target fuel and hit it with your death star accelerator and get 40 times more energy at the target.

depleted uranium around the target should utilize the neutrons.
So a fusion fission hybrid system

There is more energy generated in the shot. the paper is only the initial impact and initial ignition. The energy probably does to 100-200 nanoseconds. They just stopped the simulation so far at 50 nanoseconds.
So my guess is 3-7 times more energy. Plus I think more more energy with a faster shot.

the researchers also indicate that the diamond has structural strength to get accelerated with 10 Gigavolts/meter. So there is a lot more upside with this method

http://nextbigfuture.com/2010/07/net-12 ... ot-of.html