COMSOL simulation of a FUSOR?

[Werner Engel]

Hi!

Has anyone tried to simulate the moving/colliding ions inside a fusor using COMSOL?

BR,
Werner

PS: Please also have a look at the Invitation to the "European Fusor Meeting" viewtopic.php?f=47&t=11622

[Scott Moroch]

Werner,

Several weeks ago I did simulations of ion motion in a fusor using Simion. I have been meaning to write a post on it but have been too busy with school. I have attached some pictures of the simulations. In each of these I launched ions in a circular distribution around the grid.

The left side of the picture shows the grid orientation, and the right shows the ion motion.

Scott Moroch

[ian_krase]

Did you just buy SIMION,. Or did you have it from work or school?

[Scott Moroch]

I am an undergrad at the University of Maryland and do research in the Radiation and Accelerator Facilities. I was given a copy of Simion for the research projects I am working on.

It is unfortunate that an indefinite license of Simion is around $800-$900.

Scott Moroch

[Richard Hull]

Great stuff! As I do not have Simmon, what was the origin point of the ions? Can I assume the shell? Of course, this is the ideal in a fusor. Too bad the ions are born all over the volume in the common fusor with the vast majority never undergoing full acceleration, circulating in many smaller orbits.

Still, very interesting plots. Thanks for sharing.

Richard Hull

[Dan Knapp]

There is at least one ion optics software package, IBS, available free from sourceforge, http://ibsimu.sourceforge.net. I have never used it, but it might be worth looking into for someone who wants to do modeling and does not have access to SIMION.

[Noah C Hoppis]

IBSimu is a very good option for ion source extractor and accelerator geometries. I've used it to poke around an ECR ion source extractor with good results. I'm not sure how well it would fair with spherical geometries allowing for orbitals. A "kill" function for prolonged life ions may be necessary.

I would be interested to see where and by which mechanism the bulk of ions in a fusor are produced (ion-neutral interactions, electron-neutral interactions, etc.).

[Richard Hull]

I think we can go to the bank with the bulk of ions being produced by electron-neutral reactions via high field emission. The fusor is little different in operation from a fully controllable,
oddly electroded, neon glow lamp, partially functioning as a deuteron accelerator-collider for about .01% of its total modus operandi, producing only 1 billionth of its net applied energy in nuclear fusion energy. All the other 99.99% of the modus operandi taking place in the fusor simply heats the shell being given off as a net loss in waste heat, minus the microscopic amount of energy piercing the shell as 30kv+ x-radiation and flying 2.4mev fusion neutrons.

The above is a fairly good description of the functioning, average, amateur fusor.

In the long run, as a fusion reactor it is perhaps one of the most miserably wasteful sources of net applied energy to create fusion energy. Still, pound-for-pound and dollar-for-dollar spent compared to other fusion reactors, it is probably the easiest and least expensive fusion reactor to build and operate, making the production of real nuclear fusion a snap for the gifted amateur scientist.

The goings-on is a fusor are multi-modal; perhaps with 10 or 20 different modalities, (a witch's brew). Only 2 or 3 of these modalities are capable of doing fusion and these are the least functional of all the modalities. Of these least functional processes only the tinest fraction of their full function will ultimately produce fusion.

Richard Hull

[ian_krase]

How does this compare to a simple beam-on-target or colliding-beam-quasifusor system?

[Richard Hull]

Both of those are far more expensive and troulbesome to implement using the D-D process. While the best loaded target would be palladium, titanium seems to be the base material of choice due to expense.

Richard Hull