Aviation Week on the Lockheed Skunkworks CFR

[RodCarlson]

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[RodCarlson]

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[ohiovr]

Hi Rod Nice to have you here. Interesting. I love Faraday's experiments...

[ladajo]

I have to think on this one a bit, but little hairs are going on the back of my neck, potentially regarding neutral cycling points and field reversals, as well as gyro radius during transitions. Hmmm.

Thanks for joing the fray Rod, curious critical minds are always welcome.

[choff]

If that's how it actually works you would also have the enhancing effect of POPs on fusion output. The other thing is if it's a pure AC or AC riding on a DC bias, or if some of the magnets are DC while some are purely AC.

[hanelyp]

My impression is AC over a larger DC bias. The field with just DC is very stable in the simulations I'm doing. I see a straight AC inside current flipping the magnetic field between simple magnetic mirror and something close to a synthetic FRC, driving the plasma out hard, leaving the center space devoid of plasma.

[choff]

Wouldn't a lot depend on how fast the AC field flips, if it could switch many times before the plasma could even begin to move.

[D Tibbets]

Admittedly, the A/c or pulsed DC magnetic fields will induce motions in a conductor like plasma. I think the principles of transformers are the same. Some type of resonant plasma occilation may be usefull. But a couple of cavets that I think probably apply. If you are varing the magnetic field you are varying the plasma motions, this ossilation is creating electrostatic fields and magnetic fields in the plasma. This implies, I think, that the plasma is magnatized much as in a tokamak. As such ExB diffusion would apply to the ions and this leads to excessive losses unless the machine size is large. Also, what would these varing fields do to the geometry of the confining B fields in relation to the plasma. will edge instabilities occur. This is one of the major advantages of the Polywell,and also of the Lockheed machine (at least for the dominate plasma volume, as I interpret the Lockheed scheme).

Magnetic oscillations may help to heat the plasma, or establish density fluctuations, perhaps something like POPS. But I do not appreciate how his would help containment. It might help in fusion rates.

Alternating current in electromagnets in order to vary the geomety or pressure is doable, but with superconductors alone it would be difficult. Axillary copper coils would need to be used, if the oscilations are a major fraction of the baseline supperconductor induced B field, the energy consumption and heating of the copper would be considerable. Also, the wear and tear on the copper and possibly even the superconductor windings shifting with B field variation might be a concern.
For this reason manipulation of the plasma- essentially variable heating , may be more practical with microwaves, lasers, variable neutral beam injection, etc.

The Polywell is not a collection of positive ions in the center. It is a collection of almost neutral plasma, with a tiny excess of electrons. The spherical symmetry does lead to dynamic density and energy changes in the electron/ ion balance at different radii. The potential well is critical for ion containment, only the electrons are magnetically contained (in a simple perspective).

Also, keep in mind that cusps are not only bad for electron losses, they are good for electron injection, possibly neutral plasma or ion injection, and also essential for fusion ion product escape. the Wiffleball effect on the cusp losses is hopefully good for electron containment, while also not precluding the other requirements. They may also help to limit electron up scattering and even ion up scattering.

Dan Tibbets

[RodCarlson]

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[RodCarlson]

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[RodCarlson]

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[D Tibbets]

Changing the current in a superconductor loop is not trivial. The details are presumably complex and variable. But as an example, this link describes a way of creating a current in a superconducting magnet - charging up an MRI magnet. Times of up to 30 seconds are needed, with active heating of a portion of the coil. Changing to a superconducting frequency change of perhaps micro seconds or less would obvously require very different methods.

http://physics.stackexchange.com/questi ... cting-loop


Also, speeking of superconductors as zero resistance diamagnetic systems may be misleading.

http://hyperphysics.phy-astr.gsu.edu/hb ... /meis.html

Dan Tibbets

[RodCarlson]

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[RodCarlson]

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[RodCarlson]

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