[FrankOlson]

Don’t know what you’re asking, but check this out. Speciffically page 33 on the ‘Hypocycloidal-Pinch Apparatus’. I found it in a post somewhere in here. The article is

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19760014958.pdf

An increased confinment time was reported. Quite interesting.

Attached files

[FrankOlson]

I mean what’s the use of this insulator? It helps form the current sheath I’ve read, but it seems to be a source of headache, why not just have an insulator gap at the base? This would be easier to machine and some design parameters and optimizing would be reduced, I think. Is it really essential to the function of a DPF? Even the filippov design has the insulator going up the side, why not just gap the bottom?

[FrankOlson]

Yes, true. I found a list. Some of the side reactions I found were

p+B11->C12+gamma
p+B11->n+C11
He4+B11->n+N14
He4+B11->p+C14
He4+B11->T+C12
B11+B11->Junk
and Possible B10 impurities

From: Scott Stephens on 18 January 1998
http://home.earthlink.net/~jimlux/nuc/reactions.htm

But, the goal is bountiful p+B11->3 He4 + 8.7 Mev reactions. How are these going to be measured? How will it be known that they are happening?

[FrankOlson]

I was listening to the Oxford presentation. Pardon my layman’s knowledge in plasma physics perhaps, but as I understood, when the copper electrodes were being used, up to 1/3 or so of the plasma was impure and made up of copper from the electrode. So with tungsten, the purity issue is mostly resolved. What if the electrode, or a portion of it, was electroplated with the metalloid B11? I know there are other processes to make metals adhere to each other, but know what I mean. If a plasma is to be composed of impurities and some of those impurities are metal, why not have the metal impurity be the fuel at the same time? I read that boron 10 has not so good electrical conductivity until it’s heated to certain temperatures. I assume B11 would have relatively the same properties, so that’s not so good. Plausible?

[FrankOlson]

Any thoughts about what’s to be done with the electron beam? Pardon my “yahoo answers” style questioning, but it’s some pretty thick gravy trying to sort through this stuff. I’ve been reading about magnetrons, klystrons and and inductive output tubes. That must be the trick – to turn the electron beam into microwaves somehow, and then pick up the microwaves with a rectenna?

[FrankOlson]

That’s what I was thinking, but I wasn’t sure and I couldn’t find much for straight explanations – especially for a rogoski coil in this particular siutation/use. You explained it well, thanks for that.

[FrankOlson]

Oops, a calculation for anode length is under design parameters in wikipedia. Although they still don’t mention how the insulation length is figured.

http://en.wikipedia.org/wiki/Dense_plasma_focus

From some of the articles I’ve been reading it seems that it’s kinda of a trial and error process. I’ve attached an article that states this, it’s on page 1816.

“Unfortunately, there are still not
validated theoretical models to determine the dimensions of
the insulator. Therefore, several tests with different insulator
length and diameter, scanning pressure range from 1 to
12 mbar, were necessary to determine the size of the insulator
in order to obtain a homogeneous initial sheath.”

This article was not through the university, it can be found through google, but I’ve attached it anyway. If it doesn’t let me attach, the name of the article is

“Research on Pinch Plasma Focus Devices of Hundred
of Kilojoules to Tens of Joules”

Brazilian Journal of Physics,
ISSN (Printed Version): 0103-9733

[FrankOlson]

This team made some small, smaller, and tiny versions. Fun to read about.

http://www.redalyc.org/pdf/464/46434854.pdf

http://www.cfn.ist.utl.pt/17IAEATM_RUSFD/doc/files/proceedings/OT6.pdf

[FrankOlson]

Leopoldo, S. (2002). Braz. J. Phys. vol.32 no.1 São Paulo Mar. 2002. Brazilian Journal of Physics , 32(1), Retrieved from http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332002000100025

Attached files

[FrankOlson]

I see. I read the article on the plasma rail gun. Thanks guys. Between wikipedia and lecture 11, this is making a lot more sense to me than it did last week.

asymmetric_implosion,
You mentioned that the plasma focus circuit is a simple design on paper. It’s a capacitor in parallel with a cathode and an anode that is being gapped by a gaseous medium, essentially. Then the plasma sheath comes into play – it’s a complicated thing. So how would you represent the cathode and anode, as a resistor, capacitor, or inductor? I know there would be stray elements of each, just like in real world components. I just don’t know which would be the prevailing for this case. My guess is that it’s a capacitor until it begins experiencing a dielectric breakdown, hence the plasma, then the resistive element dominates as the actual ‘capacitor’ bank keeps discharging into the cathode and anode. But, I know once the plasma forms the resistance would probably drop since, from what I remember, the plasma is a low resistance element once formed. This all happens so fast besides, it’s just mind blowing.

http://en.wikipedia.org/wiki/Electromagnetic_forming

Lewin, Walter. 8.02 Electricity and Magnetism, Spring 2002. (MIT OpenCourseWare: Massachusetts Institute of Technology), http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002 (Accessed 23 Feb, 2014). License: Creative Commons BY-NC-SA.

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