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DeltaV
PostPosted: Sat Sep 03, 2011 5:49 pm 
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Polywell is not mentioned, explicitly. "Electrostatic confinement thermonuclear fusion" is.

Dr. Nebel is now with Tibbar Technologies (branches in NY and NM).

53rd Annual Meeting of the APS Division of Plasma Physics
November 14–18, 2011; Salt Lake City, Utah

Abstract: Electrostatic Mode Locking and Mode Suppression in RFPs and Tokamaks
Richard Nebel (Tibbar Technologies)
John Finn (Los Alamos National Laboratory)
Quote:
It is possible to lock and amplify m=1 modes from the boundary in an RFP by using electrostatic fields. Furthermore, it is possible to do this without any magnetic field lines penetrating the boundary (i.e. the normal component of the magnetic field vanishes at the boundary). These can result in single-helicity or quasi-single-helicity states which have good flux surfaces. A key to forming these states is to drive the primary unstable RFP mode to large amplitude. For the unstable modes, perturbations from the boundary amplify into the interior. These same ideas can be applied to suppressing modes as well, such as the secondary m=1 modes in RFPs or edge modes in Tokamaks. We derive the required phasings to implement this scheme. We also present a conceptual feedback control scheme for suppressing instabilities.
Reversed field pinch

Abstract: Two-Stream Instabilities, Debye Screening, and Resonant Electron Drive in a Modified Malmberg Trap
Allie Laird (Tibbar Technologies)
Richard Nebel (Tibbar Technologies)
Quote:
Debye screening caused by electron energy downscattering from electron-electron two-stream instabilities is being studied in a modified Malmberg Trap geometry. Theoretical studies are being conducted with Particle-In-Cell simulations. In particular, mitigation of these modes by resonant electron drive is being explored. A small experiment is being constructed in the Tibbar Technologies Bismark Device to test these concepts. The application of this work is to electrostatic confinement thermonuclear fusion.
The Malmberg-Penning Trap

TIBBAR TECHNOLOGIES, Los Alamos, NM
TIBBAR TECHNOLOGIES, Rochester, NY
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Giorgio
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PostPosted: Sat Sep 03, 2011 5:58 pm 
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Good find!
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DeltaV
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PostPosted: Sat Sep 03, 2011 6:11 pm 
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Giorgio wrote:
Good find!

Thanks. My Google-Fu's been rockin' lately.
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mvanwink5
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PostPosted: Sat Sep 03, 2011 6:13 pm 
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Looks like Tibbar Technologies just doubled its consulting staff. Not unusual for someone that wants to consult but not carry their own insurance to work for a small consulting firm.

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DeltaV
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PostPosted: Sat Sep 03, 2011 6:28 pm 
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http://www.talk-polywell.org/bb/viewtop ... c902#59839
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Skipjack
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PostPosted: Sat Sep 03, 2011 7:34 pm 
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Hmmm, wonder what that says about the Polywell...
Really odd of Rick to leave EMC2 and move on to different concepts, unless Polywell turned out to be a dead end. Of course this may just be me overinterpreting things. We did get a report stating "excellent confinement" after all, though that is a bit vague too.
All in all, I am more confused than ever.
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DeltaV
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PostPosted: Sat Sep 03, 2011 7:59 pm 
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Quote:
Debye screening caused by electron energy downscattering from electron-electron two-stream instabilities is being studied in a modified Malmberg Trap geometry.
Rick said earlier that two-stream instabilities are not a Polywell issue.

Quote:
Theoretical studies are being conducted with Particle-In-Cell simulations. In particular, mitigation of these modes by resonant electron drive is being explored.
This sounds possibly similar to the Periodically Oscillating Plasma Sphere (POPS) concept.

Quote:
A small experiment is being constructed in the Tibbar Technologies Bismark Device to test these concepts. The application of this work is to electrostatic confinement thermonuclear fusion.
A Polywell variant?
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DeltaV
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PostPosted: Sat Sep 03, 2011 8:42 pm 
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"Tibbar" is "Rabbit" backwards.
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rcain
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PostPosted: Sat Sep 03, 2011 11:57 pm 
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A good find indeed. Well done Delta. Good to know Rick is still on the circuit at least. Impossible to infer anything much about why he's with no longer with the US Navy/EMC however.

Re: RFP and POPS - don't see much connection myself; thought POPS was essentially a microwave RF induced phenomenon.

Perhaps we can get him very drunk and spill some beans ;)
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rjaypeters
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PostPosted: Sun Sep 04, 2011 12:31 am 
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Hey, that was my idea!

What is Dr. Park doing?

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KitemanSA
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PostPosted: Sun Sep 04, 2011 1:10 am 
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rcain wrote:
Perhaps we can get him very drunk and spill some beans ;)
Why would we want to spill some beans? :roll:

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Do the numbers... correctly, "think Hydrogen".
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DeltaV
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PostPosted: Sun Sep 04, 2011 1:15 am 
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Dr. Nebel has a research history with RFPs and (with J. Park) two-stream instability, so hopefully he's just continuing prior research as opportunities occur, rather than having abandoned Polywell.

Werley, K.A., R.A. Nebel, and G.A. Wurden, Transport description of the rise time of sawtooth oscillations in reversed-field pinches. Physics of Fluids, 1985. 28(5): p. 1450-3.

Two-dimensional electron-electron two-stream instability of an inertial electrostatic confinement device. Marocchino, A; Lapenta, G; Evstatiev, EG; Nebel, RA; Park, J Source: Physics of Plasmas; Oct. 2006; vol.13, no.10, p.102106-1-7

@rcain: I was thinking of harmonic motion w.r.t. any connection between POPS and "resonant electron drive" (Malmberg Trap, not RFPs), but I don't know enough about either to do more than suspect.

http://nextbigfuture.com/2010/08/los-al ... tatic.html
Quote:
An ion cloud (referred to as the Periodically Oscillating Plasma Sphere, or POPS) in such an environment will undergo harmonic oscillation with an oscillation frequency independent of amplitude. Tuning the external radio-frequency (rf) electric fields to this naturally occurring mode allows the ion motions to be phase-locked. This simultaneously produces very high densities and temperatures during the collapse phase of the oscillation when all the ions converge into the center.

BTW, any mention of POPS has disappeared from LANL's website...
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rcain
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PostPosted: Sun Sep 04, 2011 5:02 pm 
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KitemanSA wrote:
rcain wrote:
Perhaps we can get him very drunk and spill some beans ;)
Why would we want to spill some beans? :roll:


ok, ok - imperfectly constructed sentence.

beans = information
Rick Nebel to spill them, not us.

But i suspect you were just being obtuse ;)

Re: RFP - i thought this was considered something of a dead-end approach these days (bad confinement times, etc). Or did I miss something? Or perhaps it is just a convenient laboratory for studying Tok. stabilities.

Re: POP's - wish I knew more of the current state of the art. Has it too been declared a dead end?

Wish these research teams were more forthcoming with information.
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KitemanSA
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PostPosted: Sun Sep 04, 2011 8:56 pm 
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rcain wrote:
KitemanSA wrote:
rcain wrote:
Perhaps we can get him very drunk and spill some beans ;)
Why would we want to spill some beans? :roll:
ok, ok - imperfectly constructed sentence.

beans = information
Rick Nebel to spill them, not us.

But i suspect you were just being obtuse ;)
Right! I scaLEAN in that direction. :oops:

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Do the numbers... correctly, "think Hydrogen".
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vankirkc
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PostPosted: Mon Sep 05, 2011 2:18 am 
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rcain wrote:
Impossible to infer anything much about why he's with no longer with the US Navy/EMC however.


The optimism on this board is relentless. Brutal even.
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