Avalanche Fusion's Orbitron - Published Paper

[Nicolas Krause]

I believe this is the first journal paper of Avalanche Fusion's Orbitron concept. I have not read it yet, but posting here if it's of interest to forum members. The paper is open access and as far as I can tell from a quick skim, details their system design.

[Joe Gayo]

Thanks for sharing!

Oddly missing from the graphs and figures are neutron rates. But I'm glad they finally used some of the millions of dollars to acquire some detection gear.

[Richard Hull]

They constantly say, based on their calculations and theoretical machinations, that significant fusion rates are achievable.

They did not say they have been achieved. (kinda' significant in and of itself)

Show functional kit with numbers and data and then you may or may not have something.

Richard Hull

[Nicolas Krause]

Having given the paper a bit of a closer look I've got to say I'm not impressed. I'm not an expert in any of these areas by any means, but the paper doesn't read very well to me. I see their logic as follows

1. Ion density is the limiting factor in fusion rates
2. We've got a novel geometry that increases ion density
3. As proof here are a bunch of numerical simulations based on simplifying assumptions

I think the real part that makes me nervous is the conclusion that they just need to increase the power. That sounds a lot like people building bigger and bigger Tokamaks. "Just trust me, if we make it go to 11 it'll work!" or something to that effect. Like you've noted Joe (and Richard as well! you posted while I was typing this up), I assume an effective solution to the fusion problem would show some really impressive neutron numbers at lower power values. It really doesn't seem like a good sign that those aren't included.

[Liam David]

I could forgive the lack of neutron data if not for, among other gems:

These simulations include Coulomb collisions, using the WarpX implementation of the Direct Simulation Monte Carlo method, but the collision time at these high energies is larger than the duration of the simulations.

Which leads me to believe that they have no idea about scattering losses.

With the beam–beam velocity distribution predicted in the absence of thermalization, high fusion rates can be achieved at densities and for device scales significantly lower than traditional reactors. In practice, the ion velocity distribution will most likely be somewhere in-between a pure beam and thermal distribution, which will reduce the neutron flux. and An inherent energy loss mechanism of this device is Bremsstrahlung radiation, which is a commonly cited concern for fusion reactors with non-Maxwellian energy distributions.58 A key goal of our research is to characterize the Orbitron particle distribution functions and phase space dynamics in order to substantiate a detailed power balance analysis using the methodology described in Ref. 59.

They have no idea what their distribution function will likely be and so all the scaling relations I've seen on their conference posters are bunk. They've also done no analysis on Bremsstrahlung losses (e.g. Rider's thesis).

In the device capable of −100 kV cathode voltages, a 0.05 T magnetic field at the mid-plane (z = 0, r = 6 cm) is sufficient to confine electrons (see Sec. II A 2). For this low magnetic field, we use neodymium magnets in a Halbach array modified by a variable trim coil mounted on the mid-plane as shown in Fig. 7.

Halbach arrays have cusps so they do not have the mirror confinement in z that they claim. Electrons are likely leaving the ends immediately.

[John Fenley]

I'm not saying I like it, but they do seem to be moving a little toward the device I am working on. From what I can tell, you'd have a basic orbitron type device if you dropped a working fusor in the MRI machine I have. That was actually one of the tests I was planning to do on the way toward my final device that does not use a central electrode, but instead uses the magnetic field itself to wrangle ions to the center periodically through cyclotron motion.

[ChiefFusioneer]

Orbitron version: Neo V4 first plasma post

Linkedin: https://www.linkedin.com/feed/update/ur ... 187411456/
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[JoeBallantyne]

Hi Chief Fusioneer.

Real names are required on this forum.

If you can figure out how to do fusion, you ought to be able to read the rules and follow them.

Please update your name with your actual real name.

Which based on the links in your post appears to be Robin Langtry. Nice that you posted an update, but real names are required.

Joe.

[Paul_Schatzkin]

Thanks Joe.

People... they never cease to amaze (and not in a good way)

I've sent Mr. Chief Fusioneer an email asking him to correct his login/ID/name.

--PS

[Dennis P Brown]

They claim "ion density is the main issue"? LMAO - no. Its containment of said ions and that is the killer - if that is overcome, ion density follows. There are other major issues but putting in ions isn't it. Its holding onto to them. Liam covers those other issues well.

[Patrick Lindecker]

Hello,

I read superficially this article, so below is a superficial opinion...

This presented trap seems a clever one. However there is several general problem on traps:

* the minimum particles density. It seems that thanks to an electron confinement they reach a density 6 times better that the Brillouin limit (6E10 ions/cm3). This is nice, but to reach the standard density for fusion it would be necessary to reach a much higher density (let's say 6E13 ions/cm3 so 1000 times higher).

* these traps works well with few collisions, so to have trajectories close to the calculated (theoritical) ones. Now to have one fusion, it is necessary to have a lot of Coulomb collisions before. Certain Coulomb collisions can cause trajectories at 90° relatively to the theorical trajectories and no electrical field or weak magnetic field (0.05 T here) will prevent the ion to collide a wall. Moreover isotropization and thermalization are normal and quickly available (less than 1 second) due to the numerous Coulomb collisions. So very quickly the trajectories will be random and only a strong magnetic field can confine the particles. Now it's true that the behaviour will be intermediate between a pure beam and a thermal diffusion. And without a strong magnetic field, the ions will be rather a pure beam which will be lost on the wall after several Coulomb collisions.

* The Bremsstrahung is not the sole problem of radiation: cyclotronic radiated power and losses on high Z impurities must be taken into account.

Patrick Lindecker