Search found 78 matches

by prestonbarrows
Wed Dec 17, 2014 9:34 pm
Forum: Theory
Topic: Can anyone walk me through Field Reverse Configurations?
Replies: 23
Views: 12408

Re: Can anyone walk me through Field Reverse Configurations?

In my limited experience in this field, I have seen two general ways to form an FRC. The first is basically 'in situ' in a stationary tube. You have a solenoid with three sections. You start with static fields in each section aligned in alternating directions. You then light a low density plasma wit...
by prestonbarrows
Sun Dec 07, 2014 6:26 am
Forum: Design
Topic: direct conversion voltage and converting to grid usable AC
Replies: 15
Views: 16620

Re: direct conversion voltage and converting to grid usable

HVDC grids are on the order of 100's of kilovolts. Fusion products have energies of the order of 10's of megavolts. Below is an image of what is needed to hold off 25 megavolts at an Oak Ridge accelerator. It is 100 feet tall, 33 feet in diameter, and under 6 atmospheres of pressurized SF6... http:/...
by prestonbarrows
Sat Nov 29, 2014 8:50 pm
Forum: News
Topic: Superconductors for Fusion
Replies: 13
Views: 6710

Re: Superconductors for Fusion

I know supercritical CO2 is being looked at for closed loop exchangers in the fission reactor world. I have never heard of it being used for magnets though, interesting thought. A 5-minute look at wikipedia puts the minimum of the phase at around 1000 PSI at 90 F. This is just about the limit of sta...
by prestonbarrows
Sat Nov 22, 2014 8:31 am
Forum: General
Topic: school closed in mid november due to snow
Replies: 49
Views: 6125

Re: school closed in mid november due to snow

Thanks Obama.
by prestonbarrows
Sun Nov 16, 2014 5:30 am
Forum: Theory
Topic: simple particle simulators
Replies: 21
Views: 19206

Re: simple particle simulators

The price described for V-sim is outside my budget. MHD would be attractive if the situation I wanted to simulate had a short mean free path. For long mean free paths, such as in a polywell, I'm not seeing how that method fits. The hardware I'd be running on has what was a high end CPU a couple yea...
by prestonbarrows
Sat Nov 15, 2014 10:34 pm
Forum: Theory
Topic: simple particle simulators
Replies: 21
Views: 19206

Re: simple particle simulators

Plasma Physics via Computer Simulation is the classic on the theory of particle-based plasma codes. It outlines the algorithms and gives some coded examples. Be warned that it is dated, but the essentials are there if you are fluent in a more modern coding language. What you are talking about is kn...
by prestonbarrows
Fri Nov 14, 2014 4:09 am
Forum: News
Topic: Superconductors for Fusion
Replies: 13
Views: 6710

Re: Superconductors for Fusion

What is the current carrying capacity of copper wire? And, how much cooling can you achieve with vigorous coolent flow? It depends if you are talking pulsed or CW. For pulsed, in terms of thermal limits, the energy in your cap bank will result in a temperature rise proportional to the mass of coppe...
by prestonbarrows
Thu Nov 13, 2014 4:01 am
Forum: Theory
Topic: Non-Tokamak Perfect Magnetic Bottle
Replies: 10
Views: 4264

Re: Non-Tokamak Perfect Magnetic Bottle

Yup, or just distribution functions in general. If you could measure the energy of each particle individually in an instant of time then make a histogram of the results, you will always end up with some Gaussian-like bellcurvey graph. There will always be some particles with much higher-than-average...
by prestonbarrows
Thu Nov 13, 2014 1:36 am
Forum: Theory
Topic: Non-Tokamak Perfect Magnetic Bottle
Replies: 10
Views: 4264

Re: Non-Tokamak Perfect Magnetic Bottle

If fusor ions are leaving the core, just increase the anode voltage. Electrostatically confined particles will still upscatter to an energy higher than whatever voltage you apply to the grid. That is basically the definition of upscattering; some subset of the population will gain an energy greater...
by prestonbarrows
Sun Nov 02, 2014 2:54 am
Forum: Theory
Topic: Can anyone walk me through Field Reverse Configurations?
Replies: 23
Views: 12408

Re: Can anyone walk me through Field Reverse Configurations?

FRCs are not really my area of expertise but I know a few people who do work on them; enough to have absorbed at least the basics. The general idea is to have a large solenoid to set up an axial field. Now imagine putting a smaller solenoid coaxially inside the first and running current through it i...
by prestonbarrows
Fri Oct 31, 2014 11:32 pm
Forum: Theory
Topic: Non-Tokamak Perfect Magnetic Bottle
Replies: 10
Views: 4264

Re: Non-Tokamak Perfect Magnetic Bottle

It is very easy to make a magnetic bottle that 'perfectly' confines single particle orbits. The problem is in a real plasma you have much more than one particle and they are all interacting with each other. The classic shortcoming of any bottle is the concept of a 'loss cone' and the fact that the p...
by prestonbarrows
Tue Oct 14, 2014 5:15 am
Forum: Theory
Topic: pressure
Replies: 4
Views: 2907

Re: pressure

Pressure in the classical sense does not really apply to individual fusion reactions. Each time two particles collide, they have a certain probability of fusing. That probability (cross section) is dependent on which elements they are and their relative energies (velocities). For fusion reactions, y...
by prestonbarrows
Sat Sep 27, 2014 11:54 pm
Forum: News
Topic: New Experimental Polywell Publication
Replies: 14
Views: 10017

Re: New Experimental Polywell Publication

why the geometry mistakes of the early machines would be repeated. Bussard's results are not published. They are nothing more than anecdotes for anyone outside of his company. For all intents and purposes, they never happened. The Sydney group are really the only folks putting out rigorous peer-rev...
by prestonbarrows
Thu Sep 18, 2014 6:58 am
Forum: Design
Topic: Simulation software : OOPIC
Replies: 26
Views: 24849

Re: Simulation software : OOPIC

Being significantly off the midplane would explain the apparent 'divergence' near the origin. In that case, you would have flux coming 'out of the page' from one of the other two coils in the z direction. Gauss' law is of course is for all dimensions; I made the assumption you were on the midplane a...
by prestonbarrows
Fri Sep 12, 2014 12:16 am
Forum: Design
Topic: Simulation software : OOPIC
Replies: 26
Views: 24849

Re: Simulation software : OOPIC

Matt, I can't say for sure without access to the actual vector field you are using to plot these. But, you either have an impossible, diverging, magnetic field or the vector plot is just misleading. I think it is very likely you have an issue with how you are handling the boundary conditions and sym...