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Dependence of the virtual cathode in a Polywell on...

Posted: Thu Jun 10, 2010 7:28 pm
by MSimon
The dependence of the virtual cathode in a Polywell™ on the coil current and background gas pressure

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http://pop.aip.org/phpaen/v17/i5/p05251 ... view=print

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Phys. Plasmas 17, 052510 (2010); doi:10.1063/1.3428744 (5 pages)
Matthew Carr and Joe Khachan

Nuclear Fusion Physics Group, School of Physics A28, University of Sydney, New South Wales 2006, Australia

Floating potential measurements have been carried out on a Polywell™ inertial electrostatic confinement device that uses magnetic cusps to trap electrons and establish a virtual cathode. In particular, the dependence of the floating potential on the coil current and background gas pressure was studied. The magnetic field coils were driven by a pulsed current supply and it was found that the virtual cathode could only be established within a narrow range of currents. In addition, it was shown that the magnitude of the floating potential increased with decreasing background gas pressure. It is conjectured that the depth of the virtual cathode and its lifetime are dependent on the magnitude of the injected electron current.

Posted: Fri Jun 11, 2010 12:10 am
by ladajo

Posted: Fri Jun 11, 2010 9:51 pm
by MSimon
ladajo wrote:Dude...

viewtopic.php?t=2296
I'm sorry to say I don't keep up like I used to. The first year was easy. Last year was do-able.

This year I miss a lot. We have a LOT of new people this year. Good for Polywell in particular and fusion in General. Bad for this moderator.

Posted: Sat Jun 12, 2010 2:30 am
by D Tibbets
Virtual cathode and potential well is possible and its lifetime is dependent on current. Perhaps this is wishful thinking, but it sounds somewhat like what Bussard talked about in describing wiffleball formation. Perhaps not a direct parellel, but longer well lifetime with proper current in their pulsed example, is in effect a method to increase the containment time of the electrons, which is what the Wiffleball does. IE: different vocabulary to describe the same effect.

Dan Tibbets

Posted: Sat Jun 12, 2010 3:01 am
by Tom Ligon
Sounds vaguely like the results of the earlier HEPS device. They could drive it to a deep potential well, but only with little plasma present.

Posted: Sat Jun 12, 2010 12:56 pm
by KitemanSA
ladajo wrote:Dude...
viewtopic.php?t=2296
Greeting folks,
If you know of a topic or piece of info that is GENERALLY important to the understanding of Polywell and can think of a good "FAQ" and answer, PLEASE provide it and I will insert into the FAQ. Better yet, get yourself signed up as a FAQ editor.

Also, "back the FAQ", push it, back it up. It COULD be a great tool rather than the fairly anemic one folk show it is now.