Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: IEC Simulation
Date: Aug 20, 6:20 pm
Poster: Mark Sloan

On Aug 20, 6:20 pm, Mark Sloan wrote:

>>At the University of Illinois they use approximation programs to simulated IEC operations in PC's.
>>I know that the best simulations don't even come close to what an IEC will do.
>>So the question is, why are simulations so far off the mark on these device?
>>Anyone have an opinion on this?

Perhaps there is some real physics that everybody is missing, but my guess is that the biggest problem (if they have one) is just the complexity of many simultaneous effects

With regard to amateur use of computer codes,this code would probably be very difficult to use even if for some reason they let it out. As Richard says, simulation programs for complex devices often have a lot of approximations, fudge factors and knobs to turn (sometimes even based on real data). So many in fact, that often the only people who can get useful answers are the people that wrote the code and understand what's in it. My guess is that the above code would be in this category.

However, that code doubtless also contains subroutines for a lot of straightforward physics. These probably include fusion and coulomb scattering cross-sections, mean free path, plasma energy loss rates, and the like. I expect the subroutines could be assembled in small programs (perhaps even run from Excel so you can easily plot the results and change the inputs) to give at least some simple answers about what is important and what is not. For instance, if an ion with a given energy hits a plasmoid of a given temperature, density, and species concentration, what % of the time will the ion fuse, rather than just scatter in the plasma till it comes to thermal equilibrium? Or, how many ions/sec do you have to hit the plasmoid with to keep it at a given temperature? Fairly simple questions should be easily answerable for whatever specific cases and reactions the user is interested in.

I think it would be a noteable contribution if such a set of subroutines, (just of straightforward physics), could be assembled and put in the public domain.

Anyone have contacts at the University of Illinois or Princeton, or ?, who might have such a set of subroutines and be willing to publish? Or who could point out where they are already available?