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MTd2 wrote: So, Bremsstrahlung are not significant for Hydrogen at 50KeV, right?

I wrote that they ARE significant. (which is why it is a good idea to recover x-rays).

But that they do not dominate. Oh, and 600 keV is the target.

I suppose that, given the expected configuration of the plasmoid, it will be possible to calculate the losses.

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Bremsstrahlung losses are significant. but just not significant enough to dominate.

in the high fields, the ions cant transfer their energy to the electrons, which remain relatively cool. this difference is quite striking, and results in much lower Bremsstrahlung losses.
(i don’t have precise measures, but guessing ~50 keV? electron T, compared to 600 keV ion T).

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the ions are flowing along the surface of a toroid. the greater angular momentum, the more stretched is the spring. the toroid’s radii both shrink together. the smaller it gets, the stronger the fields, and the higher temperatures can get. particles don’t reach the centre of rotation until the transverse part of their momentum drops to zero

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MTd2 wrote: I mean before the fusion happen, while the plasmoid is shrinking.

yes. unless the angular momentum is strong enough

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MTd2 wrote: 3. Wouldn’t the contents of the plasmoid be pushed out like a tooth paste?

eventually, they are. that’s the exit beam. and it should consist of the higher-velocity fusion products that have lower angular momentum

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MTd2 wrote:

To understand how this works, you have to understand that charged particles like to follow magnetic lines. If there is no external magnetic field to guide the ions and electrons, they converge in a chaotic mess when the filaments combine, losing energy in the process. .

The LPP site says that the intensity of that magnetic field has the magnitude of earth’s, which is 0.5 gauss. The converging filaments is like an infinite solenoid. But the one inside the solenoid, near the equilibrium point, goes up to 1.2 billion gauss, that is 9 orders of magnitude higher and any bending of the solenoid would create a non-zero radial, whose projection on the perpendicular could locally disturb the guiding magnetic field. In this case, there would be chaos.

I still don’t see a solution for that.

right-hand rule would tend to give the field lines pinching in a closed ring, (rather than an open cylinder) and the ions tracing a toroid, trapped by that ring

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Rezwan wrote:
Yes! We want to find the people who are ahead of the curve. The ones that will deserve the bragging rights, among other things.

As a boy, i was inspired by science fiction that told stories of colonizing space, and seeking the stars.
Stephen Hawking was quoted as saying that humanity must do this, to assure the survival of our species.

The world needs fusion, now.

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MTd2 wrote: I don’t understand car analogies very well, although I have a car. But from what I got of the linked LPP website, the problem was finding the ideal angular momentum of the converging filaments.

So, what I really want to know if finding such angular momentum is turning out so troublesome that might lead focusfusion completely impractical for generating energy, and this is the cause for the delayed news.

no. finding that sweet spot, the right amount of angular momentum, will be the easy part.

afaik, the current activities are focused on getting switches firing precisely in sync, and preparing for decaborane fuel.

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Aeronaut wrote: Langley blew a bunch of his capital on engine development before he had working lift or control systems. The Wright brothers built their theory and experiential base using gliders. This may cross into the fusion arena as the debate about electromagnets vs self-induced magnetic containment fields.

it’ll be about efficient power conversion technology. specifically,
how do you collect and transform 100 to 200 kJ of electromagnetic energy in a few nanoseconds?

the equipment starts to look just like a small particle accelerator coil,
eg: wound on a torus, with wide, race-track turns of thin sheets, arranged radially.

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the universe, in its infancy, had less entropy than it does, now. but i see no definitive need for a big-bang.

an information-theoretic view of the universe would tend to yield expansion as a necessary result.

in keeping with a quantum outlook, a universal observer (operating outside of the system itself) could run it backwards and restart at any point, “to see all that is, was, or could be.”

begin with the smallest universe in which time can be reversed, in this way, and have it perform arithmetic calculations, without dissipating any heat (it is therefore an isentropic process). for some kinds of logic calculations, e.g. (A or B -> C), you can only reverse if you keep extra information (given C, was it A, or was it B, that was true? there are three possible states: “A and ~B”; “B and ~A”; or “A and B”).

you need dissipate heat only when you run out of space. but if the universe must expand, then there is always enough room.

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remember that the parameters R, L, and C are a natural part of the circuit. R comes from the resistance of the feed wire, etc. The whole point of ZCT techniques would be to use multi-phase resonance, and switch at precisely the right time, so there is zero stress on the switches.

if you need a 24-phase (or more) circuit to accomplish that, i think we’re okay.

if you can put up with a 300V transition on a 50kV feed, you can still select your firing rate.
but even that transition could be eliminated with additional small-resonance circuitry.

bringing this back to the topic of history, here’s a 1989 U.S. patent for an alpha-particle capture coil:
— http://www.freepatentsonline.com/4835433.pdf

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Brian H wrote: Eric, could the switches have been made adequate then? That seems still to be a choke-point.

An electrical engineer suggested to me, to do away with the switches (and the capacitors, except for the first shot) and build a resonant circuit. The exit beam would then drive the next pulse, directly. zero-current-transition techniques generalize to the megawatts.

— http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1248264
— http://www.researchgate.net/publication/34763176_Unified_zero-current-transition_techniques_for_high-power_three-phase_PWM_inverters_electronic_resource_

zapkitty wrote:
… but this would solve the caps lifespan issue, right? 🙂

Yes. The more i think about it, the more it seems just like catching the energy from lightning.

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“It was not until World War II, when sufficient resources were finally applied to finding the causes of electrolytic capacitor unreliability, that they started to become as reliable as they are today.”

without electrolytic capacitors, a glass ceramic capacitor array, of 129uF @ 50 kV, would fit onto a spherical shell, 5m average radius and 1.5 m thick (assuming 100 plates, spaced 15mm apart). The reactor would be, easily, as big as a house.

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Brian H wrote:

In October 1745, Ewald Georg von Kleist of Pomerania in Germany found that charge could be stored by connecting a high voltage electrostatic generator by a wire to a volume of water in a hand-held glass jar

So you just need a bigger jar.

Switching and discharge within a few 10s of ns? I doooonn’t thang sew! :grrr: :bug:

that depends on the size of the wire. if 50 ns is the needed rise time (= 1/2 wave, ie: 10MHz), and you can tolerate a .006 ohm resistance, the skin effect limits the wire dimensions (in copper, ρ = R·Area / length = 1.68×10^−8 Ω·m; skin depth= 20.5 μm @10MHz) to a length no more than 7.2 x the circumference.

“The effect was first described in a paper by Horace Lamb in 1883 for the case of spherical conductors, and was generalised to conductors of any shape by Oliver Heaviside in 1885.”

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Condo developers will frequently pre-sell a bunch of units, before breaking ground on a subdivision. Of course, they don’t have to invent construction methods and materials; and the units they’re selling are pretty-well known to work exactly as specified. How far away from ability to do this is focus fusion? Not that far, really.

But there is engineering work, to do. Capture the imagination of masters and phd students, causing demand for academic courses on the science and engineering of the reactor core as well as ancillary technologies of power capture, conversion and storage. Teach those courses, giving students the drive to advance the state of the art in these areas.

Make and sell spin-off technology?

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