Talk-Polywell.org

Session RM2 - Mini-conference on Plasma Propulsion III.
ORAL session, Friday morning, November 19
Room 105/106, SCC
[RM2.008] Self-organizing plasma behavior in multiple grid IEC fusion devices for propulsion
Thomas McGuire, Carl Dietrich, Raymond Sedwick (MIT Space Systems Laboratory)

Inertial Electrostatic Confinement, IEC, of charged particles for the purpose of producing fusion energy is a low mass alternative to more traditional magnetic and inertial confinement fusion schemes.

Experimental fusion production and energy efficiency in IEC devices to date has been hindered by confinement limitations. Analysis of the major loss mechanisms suggests that the low pressure beam-beam interaction regime holds the most promise for improved efficiency operation. Numerical simulation of multiple grid schemes shows greatly increased confinement times over contemporary single grid designs by electrostatic focusing of the ion beams. An analytical model of this focusing is presented.

With the increased confinement, beams self-organize from a uniform condition into bunches that oscillate at the bounce frequency. The bunches from neighboring beams are then observed to synchronize with each other. Analysis of the anisotropic collisional dynamics responsible for the synchronization is presented. The importance of focusing and density on the beam dynamics are examined. Further, this synchronization appears to modify the particle distribution so as to maintain the non-maxwellian, beam-like energy profile within a bunch. The ability of synchronization to modify and counter-act the thermalization process is examined analytically at the 2-body interaction level and as a conglomeration of particles via numerical simulation.

Detailed description of the experiment under development at MIT to investigate the synchronization phenomenon is presented.

http://flux.aps.org/meetings/YR04/DPP04 ... 00008.html

The same as Bussard stated in his Google video.

Polywell = Non-Maxwellian plasma. Hence does not thermalise to any major degree

So the energy looses are not so big as those calculated by Rider

Nice to hear it from an independent source.

BTW self bunching at a resonant frequency is a klystron type phenomenon.

Because the resonance is natural it should (in theory) be possible to feed in power in or out of phase to control the amplitude of the oscillations.

There are some nice pictures at the MIT site showing how the beams bunch.

I also saw a simulation today. I forget where.

Here is where I saw the simulation:

http://fusor.net/board/view.php?bn=fuso ... 1189466065

MSimon wrote: Because the resonance is natural it should (in theory) be possible to feed in power in or out of phase to control the amplitude of the oscillations.

Very nicely said. People, the thing to realise here is that fusion output squares as the density of the ion species increases. Hence if we can drive (with rf) the plasma's naturally resonant expansion and compression we can increase fusion Q up a magnitude or two and hence bring us closer to break even power.

although i found this on the fusor thread

http://fusor.net/board/view.php?site=fu ... 1189618432

Im not sure what part of the machine it is meant to represent but it looks very disordered to me.

It looks like the polywell is definitely gaining momentum with MIT students verifying some of Bussards theories. Thomas McGuires paper on synchronization is out of this world

MSimon,

Don´t be shy of linking your website. You have done a very good summary !!!

http://iecfusiontech.blogspot.com/2007/ ... -here.html

So, as I see it, your getting a tuning kind of like standing waves.

In this case your talking about density standing waves. Or maybe i'm completely missing it.

If that is so, then is it better for your fusor to be tuned to generate the maximum amount of standing waves?

Is it possible to get an antinode at the very center to maximize particle density?

With standing waves in strings, a fixed end point will be a node, but a free end point would be an antinode? Been out of collage too long.

Would a fusor have a free endpoint in the center?

I think this is a natural bunching caused by the interaction of incoming and outgoing particle beams.