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by Art Carlson
Thu Jul 03, 2008 7:50 pm
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

The latest picture from Carter is wierd. I don't understand it at all, especially since he seems to be using square coils, where I would expect such effects to be smaller. Is there a significant difference between the electron trajectories and the field lines? Can you give us a picture of the whole ...
by Art Carlson
Thu Jul 03, 2008 2:10 pm
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

I did this plot several months back of individual electron trajectories. As you can see the line cusps receive nearly zero flux. Only one path actually penetrated the line cusp from all the trials, it myst hit the cusp directly or the internal structure of the magnetic field funnels any electrons h...
by Art Carlson
Wed Jul 02, 2008 7:10 pm
Forum: Theory
Topic: Carlson and Nebel
Replies: 108
Views: 44521

impression that Bussard erroneously thought he could turn a bi-conical cusp into a configuration with only point cusps by adding more coils That seems like a good summary of the concept. So I gather your main contention (at the moment) is that this won't actually produce all point cusps: it will le...
by Art Carlson
Wed Jul 02, 2008 3:49 pm
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

Re: Why is polywell supposed to be better than cusp confinem

Of course, compared to a cusp machine, the polywell may also get some credit for density peaking and recirculation (although I will question both of these effects), but it seems certain that line cusps will be a killer, and it seems pretty sure to me that line cusps are unavoidable." To me, fr...
by Art Carlson
Wed Jul 02, 2008 2:05 pm
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

I'm sorry I don't have time to respond immediately to all the responses. In particular I would like to talk in numbers concerning the consequences of a super thin current layer. But I'll make a couple quick comments right away. Since Mike Holmes thinks hanelyp raised some interesting points, I will ...
by Art Carlson
Wed Jul 02, 2008 6:03 am
Forum: Theory
Topic: Carlson and Nebel
Replies: 108
Views: 44521

Art - the answer to the first salvo was homework: # Bussard, Robert W., King, Katherine E., "Electron Recirculation in Electrostatic Multicusp Systems: I-Confinement and Losses in Simple Power Law Wells," 1991, EMC2-0491-03 Yeah. I got the assignment and finished it before writing my late...
by Art Carlson
Tue Jul 01, 2008 8:41 pm
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

Re: Why is polywell supposed to be better than cusp confinem

More basically, it looks like the polywell should be classed as high beta cusp confinement. I'm not familiar with the details, but I know that this idea is as old as the hills and was rejected very early. Why is the polywell supposed to be better? Possibly it is the idea of using point cusps instea...
by Art Carlson
Tue Jul 01, 2008 7:47 pm
Forum: Theory
Topic: Carlson and Nebel
Replies: 108
Views: 44521

The man in charge of this spectacle claims they have achieved high power and have clearly not rejected the idea. That, if mr. Carlson cannot fire a little more convincing salvos at it, ought to be enough to justify some polywell daydreaming. Me? I've been holding back to give somebody a chance to a...
by Art Carlson
Fri Jun 27, 2008 8:54 am
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

Re: Why is polywell supposed to be better than cusp confinem

There used to be a Polywell wiki but it never saw much traffic and now it is gone. Too bad. I've been thinking that this BB format is sometimes hard to follow, and it's easy for content to get lost (and therefore at best rehashed). A wiki format with the Wikipedia rules against original research re...
by Art Carlson
Fri Jun 27, 2008 8:39 am
Forum: Theory
Topic: Carlson and Nebel
Replies: 108
Views: 44521

Pardon me if I have it wrong, but I thought the "twisting" motion was produced by currents internal to the plasma, and not a product of the external magnets. If so what then keeps the internal current stable and in the "center". Yes, the twisting in a tokamak comes from internal...
by Art Carlson
Thu Jun 26, 2008 4:42 pm
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

Then you would be Rick. Seems appropriate to use first names among scientists and also for an internet forum. Call me Ishmael. My thesis advisor was George Vlases. The LANL folks are more likely to know Fred Ribe. My actual thesis experiment was done at Mathematical Sciences Northwest, whatever it m...
by Art Carlson
Thu Jun 26, 2008 1:30 pm
Forum: Theory
Topic: Carlson and Nebel
Replies: 108
Views: 44521

Concerning questions from several authors about tokamak physics: The radial electric field in a tokamak is a very important parameter that is thought to influence the confinement by up to a factor of two. What's important is actually the gradient in the field (the curvature in the potential). The pi...
by Art Carlson
Thu Jun 26, 2008 1:19 pm
Forum: Theory
Topic: Carlson and Nebel
Replies: 108
Views: 44521

Indrek, what physics is your model based on? 1-fluid/2-fluid MHD, PIC, ballistic ions, Boltzmann electrons??? What does the 3-d structure look like? Is the central well a well in all directions, or could it be that it is even shallower (or non-existent) in the directions of the corners of the cube?
by Art Carlson
Thu Jun 26, 2008 8:31 am
Forum: Theory
Topic: Why is polywell supposed to be better than cusp confinement?
Replies: 74
Views: 30501

Why is polywell supposed to be better than cusp confinement?

Greetings! After some interesting though inconclusive exchanges with some of you on cosmiclog.msnbc.msn.com, I thought it would be fun to drop by here. Allow me to introduce myself. I have a Ph.D. in plasma physics from the University of Washington, where I worked on Field-Reversed Configurations. A...

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