Tri-Alpha article published 2 may 2011

[Munchausen]

The only thing that could go wrong, is that their scaling laws are off,

Isn't that what has gone wrong in every promising fusion energy concept to this date?

[bennmann]

Touche Munch. Except for the recent Alan Boyle polywell article with some general neutron numbers for WB-8, I think you're correct.

[Ivy Matt]

Do you mean this?:

"This machine should be able to generate 1,000 times more nuclear activity than WB-7, with about eight times more magnetic field," said Park, quoting the publicly available information about WB-8. "We'll call that a good success. That means we're on track with the scaling law."

Sounds like a forward-looking statement to me.

[KitemanSA]

Do you mean this?:

"This machine should be able to generate 1,000 times more nuclear activity than WB-7, with about eight times more magnetic field," said Park, quoting the publicly available information about WB-8. "We'll call that a good success. That means we're on track with the scaling law."

Sounds like a forward-looking statement to me.

But 8X field is SUPPOSED to provide 4000 X more activity. Hmmm.

[Skipjack]

Yeah, but as I said, if they get their scaling laws wrong, then so will most likely all toks and spheromaks as well.
And that seems highly unlikely...

[Joseph Chikva]

I think that the reactor proposed by John Slough of Helion is the most realistic and down to earth concept that has the best chance of working in the near future. They do already have a working subscale prototype. The only thing that could go wrong, is that their scaling laws are off, but that would then be the same problem for most other FRC and Tok concepts. So given the experience and state of the art knowledge it should be ok.
Of course mistakes can always happen.

Sorry, this is only speculation confirmed with nothing.
I did not know who proposed Helion concept. As I mentioned I saw only their animation.
And sure that colliding plasmoids will not merge but will destroy each other scattering smaller drops to any directions.

[Skipjack]

I did not know who proposed Helion concept.

John Slough.

And sure that colliding plasmoids will not merge but will destroy each other scattering smaller drops to any directions.

Nope, they build a prototype and got reproduceable, measureable results. Those results were published recently in a peer reviewed paper.
http://iopscience.iop.org/0029-5515/51/5/053008
I got the paper before it went behind the pay wall. It looks solid.

[Joseph Chikva]

I did not know who proposed Helion concept.

John Slough.

And sure that colliding plasmoids will not merge but will destroy each other scattering smaller drops to any directions.

Nope, they build a prototype and got reproduceable, measureable results. Those results were published recently in a peer reviewed paper.
http://iopscience.iop.org/0029-5515/51/5/053008
I got the paper before it went behind the pay wall. It looks solid.

Ok, thanks.
Yes, I can not understand till now how only with big solenoid 10T can be confined plasma but also I see that at least abstract is written by qualified persons.

[zapkitty]

Ok, thanks.
Yes, I can not understand till now how only with big solenoid 10T can be confined plasma but also I see that at least abstract is written by qualified persons.

Try looking... even a blind man found the sources easily enough (raps Joseph with a somewhat battered white cane )

http://msnwllc.com/Nuclear_Fusion_IPA.pdf

... it's at that site because, like a DPF, it can make a nice practical space drive as well as a fusion power core.

[Joseph Chikva]

Ok, thanks.
Yes, I can not understand till now how only with big solenoid 10T can be confined plasma but also I see that at least abstract is written by qualified persons.

Try looking... even a blind man found the sources easily enough (raps Joseph with a somewhat battered white cane )

http://msnwllc.com/Nuclear_Fusion_IPA.pdf

... it's at that site because, like a DPF, it can make a nice practical space drive as well as a fusion power core.

Thanks again. I also understand your irony.
But I do not have any doubt in possibility of acceleration of plasmoids. I know that is possible. And this is done and used for many applications – to create and accelerate cold plasmoids.
Also I know about some fusion concepts using field reverse configuration (toroidal Z-pinch, Astron)
But:

The configuration has net bad magnetic curvature and is susceptible to MHD interchange and kink modes. When isolated from the vessel wall by an external axial magnetic field, as is typically the case, the FRC poloidal field represents essentially an anti-aligned dipole with regard to the external field and is therefore disposed to tilt instability.

Then:

Despite these daunting issues, stable high-temperature FRC plasmoids have been readily
formed where the requisite plasma heating and current generation was produced by rapid reversal
of the axial magnetic field in cylindrical coil geometry. Once formed, the FRC is observed to be
stable and the plasma well confined as long as the plasma remains in a kinetic regime.

Ok, very well. So, we have successfully formed and accelerated plasmoids. Then merging of those two is required in the field of strong solenoid direction of which will be toward for one toroid's motion direction and opposite for another.

Do you think that behavior of toroids will be like infinitely viscous liquid?

[tomclarke]

Slough thinks the field keeps things together when the FRCs merge;

In the initial experimental configuration, the FRC was dynamically formed and injected into a larger chamber to study the merging process without the complications of compression and additional acceleration. The merging chamber consisted of a 0.14 m radius quartz cylinder lined with a 0.3 m long cylindrical, thin tungsten liner. A suitable bias field of 0.1 - 0.2 T was embedded inside this liner to radially confine the FRC plasmas during merging, while two multi-turn coils provided for a small mirror field (~0.2 T) on either end of the chamber. An array of external flux and Bz field loops were installed under each coil as well as an axial array of Bz probes inside the tungsten shell. From this array the excluded flux due to the presence of the FRC was obtained, and the FRC velocity, radius, length, and energy was determined. A HeNe laser based interferometer measured the cross tube line density at the axial midplane. From this diagnostic and the magnetic measurements, the plasma density and pressure balance temperature were obtained. Deuterium plasmas were employed and a calibrated neutron detector was positioned radially outside the magnets at the chamber center to measure the D-D fusion neutron flux.
The ratio of FRC directed velocity to thermal velocity was found to be greater than three. The merging and conversion of the FRC kinetic energy was observed to take place on the Alfvenic timescale. The distinct difference between merging and the simple passage of the FRC unopposed
is clearly demonstrated in the array of excluded flux signals in the interaction chamber as illustrated in figure 4. The two FRCs merged as they collided to form a single FRC indicated by the peak diamagnetism appearing and remaining at the axial midplane. It is worth noting that with merging the excluded flux increased by a factor of at least four greater than observed for the transiting FRC.

So I guess this is why they do not just shoot pass each other.

Although he appears to have only 10% transfer KE to thermal energy from this, if this means what I think it means. So that would mean they did mostly go past each other. Or does the factor 3 relate to the input FRC characteristics?

[Joseph Chikva]

So I guess this is why they do not just shoot pass each other.

Although he appears to have only 10% transfer KE to thermal energy from this, if this means what I think it means. So that would mean they did mostly go past each other. Or does the factor 3 relate to the input FRC characteristics?

Do not know.

But know that only about 30% of neutrals injected into TOKAMKs can be absorbed by plasma. The rest 70% hit the walls.
Plasma's density in TOKAMAKs has 10^20m^-3 order of magnitude and large size, neutral beam's density - about 10^16m^-3 order.

Here we have two small plasmoids with unknown density.

[Skipjack]

The observed particle confinement, stated in terms of
directly measured quantities, that can be accurately measured
across all experiments, yields the following scaling [5]:
τN = 3.2 × 10−15ε0.5x0.8
s r2.1
s n0.6, (2)
where xs is the ratio of the FRC separatrix radius, rs, to
coil radius, rc. With reasonable assumptions for the FRC
relative size and shape (ε ∼ 15 and xs = 0.6 ), this
scaling, together with kinetic condition, determines the plasma
radius and density required to satisfy the Lawson criteria for
fusion gain, i.e. n0 1.5 × 1023 m−3 and rs 7.0 cm.
The high plasma energy density implied by these constraints
prescribes a small, pulsed fusion regime for the FRC. These
FRC parameters, together with the required temperature and
confinement, however, have not been obtained by any of the
formation methodologies that have been employed in past
experiments.

[Joseph Chikva]

Ok, thanks. I missed that numbers.
So, projected number density in toroids 1.5E23 m^-3 and size 7 cm.
And we need about millisecond confinement time of merged toroid.
I doubt that it is possible if taking into account that we will have only axial magnetic field in merging zone. Even if that field will 10T.

[Skipjack]

I doubt that it is possible if taking into account that we will have only axial magnetic field in merging zone.

He already did it though, albeit at a smaller scale.