Reply To: would nuclear energy really be accessible to all?

[JimmyT]

Allan Brewer wrote:

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Its still correct however that assuming the expected 10-20% inefficiency there would be 4-8MWatts of heat to remove from the system – which is challenging – its just that the heat is not arising from electrode resistance.

I’m curious what inefficiencies you envisage. Heat is directly generated in the plasmoid, and some losses would be expected in the ‘onion’. What others do you see?

Well that’s really the question I have been asking during this thread. I started with Rezwan’s posting https://focusfusion.org/index.php/site/article/how_will_we_get_there_from_here/ which not unreasonably expects unspecified inefficiencies of that order. I suspect you are right that the 70KJoules of energy to form the plasmoid will not all come out with the fusion energy into the Rogowski coil, and the onion will be less than completely efficient capturing the X-rays’ energy.

The problem of efficient energy capture from the ion beam is pretty fundamental. We are not sure what the velocity distribution of the ions is going to look like. The best guess is a Boltzman distribution. At any rate, the particles are not all going to be traveling the same speed. You must design the system to capture the maximum energy … But…

Let’s say you design your system to go after particles of 65Kev and were able to capture all the energy from them. Any particles of energy less than that would be decelerated, stopped and reversed by the induced magnetic field. Accelerating them back into the reaction chamber and taking some energy with them. Any particles faster than that will still have their residual velocity (the amount in excess of 65Kev ) when they reach the helium catchment container (Which thus may need cooling.)

There may be a way to mitigate this problem by using multiple coils. But I’m not sure how we would do that exactly.

We can hope that the velocity distribution is more uniform than a Boltzman distribution, which would make energy extraction more efficient. And the recent insights into plasma heating mechanisms may support that.