Reply To: Proliferation?

[Joseph Chikva]

jamesr wrote: A couple of points…

Although you mention briefly ion scattering, I don’t think you appreciate the stability (or lack thereof) of the conditions you are trying to achieve.

You will get wave-particle interactions, coupling to all sorts of kink and ballooning modes. The plasma instabilities will grow on a much faster time-scale than can be controlled, and hit the walls within a microsecond.

A linear design would have to be hundreds of kilometres long, and a ‘cyclic’ design is essentially a Tokamak, ie governed by all the same stability criteria of q-profile, Troyon limit etc.

Also the acceleration of ion/electron beams to high energies is not efficient enough – you will never get the Q number you claim.

Claimed Energy Gain Factor is defined like to other experiments – without considering of efficiency of energy conversion cycles.
This number only shows how wide area we have.
For example, if considering real efficiency of cycles involved in TOKAMAKs, net energy will go from there only after ~600s of confinement.

Acceleration of electrons by induction linacs – 35% effeciency (produces flat-top pulse using 100-200 inductive cavities)
Acceleration of ions by gas-puff magnetically insulated ion diodes – 70% efficiency (produces wide spread bell-like pulse)
We can accelerate ions by diode to lower energy. e.g. 150keV adding then e.g. one induction cavity (Inductive Voltage Adder) on 150keV for Tritons and two Adders for Deuterons. This trick would dramatically reduce the spread but at the same time also would a little bit reduce efficiency as well.
In any case acceleration efficiency will not be less 35%
So, energy has to be pumped in to the beams and specified per each occurred fusion event would not be more than:
2.26MeV/0.35=6.46MeV

From the other side using only thermal cycle with 40% efficiency we will have:
19.62MeV*0.4=7.8MeV

Or 1.36MeV from each event gained from thermal cycle

Plus energy from direct energy converter. Here we also should consider that energy initially pumped into the beams does not lose but can be recovered with some efficiency.

Regarding instabilities:
For already at least 30 years people learned up how to fight with kink and sausage instabilities in Z-pinch and TOKAMAKs.
Longitudinal mag field is very effective against short wave instabilities. Long wave kink instability has also long development time and, so, that can be eliminated by means of feedback and electrostatic quadrupole. This trick is also proposed for Heavy Ions Fusion experiment.

Balloon effect is not issue for proposed method at all.

I mentioned scattering briefly because that is well known for auditory for whom that Poster is prepared.

I also mentioned G.I. Budker and his “Stabilized Electron Beam” paper in wich is claimed that Bremsstrahlung in proposed formations is very effective against most types of instabilities. As electrons moving in very strong self-magnetic field lose not only axial coherent energy but also radial energy as well damping effectively all types of waves.
http://resources.metapress.com/pdf-preview.axd?code=r6570k3897767838&size=largest

Strong magnetic self-focusing causes characteristic electromagnetic radiation which tends to damp out transverse electron oscillations. If certain other conditions are also satisfied, this effect causes the beam to contract into a thin thread-like structure with enormous electric and magnetic field at the surface and which is apparently a stable and long-lived configuration.

So, we have two stabilizing factors:
• Longitudinal (toroidal) mag field
• Bremsstrahlung

And taking into account that confinement scheme is very similar to TOKAMAKs and we have temperatures on orders of magnitude lower than in TOKAMAKs, we can wait that feasible confinement time will be at least not less than in TOKAMAKs (seconds order). And we need only millisecond order confinement time.

Linear design needs not hundreds but a few kilometers length. Comparing with e.g. LHC’s circumference this is not so bad. As linear design has not some limitations of cyclic.