[Henning]

Found this link on Famulus’ Tweets: MACOR

MACOR is a machineable glass-ceramic developed and sold by Corning Incorporated. It is a white material that looks somewhat like porcelain. MACOR has excellent thermal characteristics, acting as efficient insulation, and stable up to temperatures of 1000 °C, with very little thermal expansion or outgassing. It can be machined into any desired shape using standard metalworking bits and tools.

MACOR has a density of 2.52 g/cm^3, and a thermal conductivity of 1.46 W/(m·K). Its low-temperature (25 to 300 °C) thermal expansion is 93×10^-7 m/(m·K). Its compressive strength is 50×103 lb/in^2. Nominal engineering properties are comparable to borosilicate glass.
MACOR is a very good insulator with excellent tolerance. Even with temperature changes, its low thermal expansion ensures that its shape changes very little.

Maybe usable for spark plugs insulators.

[Henning]

That’s a range of maybe 1kW to 1GW. Yes, the engineering challenge is the heat transport, as mentioned earlier.

[Henning]

Polywell’s minimum power output is 100MWe. That’s because of its scaling law of size^5.

I’m not quite sure about FF’s limits itself, because DPFs scale linearly in respect to their size. So theoretically anything between beer-bottle-sized (for the whole device, but adding the cooling system) and big-factory-sized should be possible in maybe 30 years — if it’s possible at all.

[Henning]

tcg wrote: Aeronaut brought up an important point — the jobs which could be created. In my small town of 30,000, we would need perhaps twenty generators for electricity and several more for water purification. Someone would have to build them, and I would imagine a good manufacturing location would be in a state with idle factories and skilled people needing work. Someone else would have to install these facilities, and others run them. This is a good time to be pitching jobs.

Won’t work. For every job created, two are lost – or take any other arbitrary multiplier. Could be 2 like in this example, 5, 10, 0.5, -2, or whatever, depending on the agenda of the speaker.

[Henning]

I’m not sure how you would get a 100ns rise time for 50kV/2MA with an RLC circuit without loosing most of the power to resistors. Or choose LC / RC / RL circuits if you like, which are in reality RLC circuits, just with one of the factors being very small. Then I’m not an electric engineer, so prove me wrong.

Remember: You don’t get a perfect signal from the induction coil + photovoltaic system + steam turbine. At least the input of turbine is mostly independent of the fireing rate. And even if you only take into account coil + photovoltaics, you’re getting in only a relatively shallow input with a rise time of maybe a millisecond.

Additionally to that you’ll need different resonating circuits for different firing speeds. Here you need the switches again to connect the different circuits to the DPF, but with less strict specifications.

[Henning]

vansig 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_

I think they don’t say anything about a current rise time of 100ns from 0 to 1 MA with a resonating circuit. That’s the problem.

[Henning]

MTd2 wrote: This update was available for 4 days, but it was absent from the focusfusion.org main page. I just saw the news when checking Next Big Future blog.

Aaron/Rezwan: This means you need to coordinate the press releases better. 😉

Like:
– Aaron: Send release to stakeholders (stockholders + Rezwan)
– 2(?) days delay
– Rezwan: send release to FFS members (including Aaron as a feedback, so he knows he can publish soon)
– 3 days delay
– Aaron: publish on LPP site (optional)
– Rezwan: publish on FFS site
Or something like it.

[Henning]

Suppose we don’t get enough energy out of coil and onion for break-even, the thermal system needs to get to its operating temperature. That means, we’ll need the energy of maybe a few thousand shots of the DPF. So a petrol engine in combination with a conventional generator (or similar) needs to provide enough electricity continuously to recharge the capacitors enough before the system runs at its desired frequency. The first shots may take place every ten seconds or so, getting gradually faster.

Pretty much what James writes, but with respect the thermal system is needed to come into gear before the FF device can support itself.

[Henning]

I don’t know about this particular article, but I read an article recently where the mobile phone is just the remote control of a supercomputer. Wouldn’t make much sense for our kind of simulations anyway, because you’ll need tight coupling of the processors.

[Henning]

In vacuum? 15m^2 for 5MW? Really? Sorry, I just didn’t know. So with atmosphere you’ll wouldn’t need a water-driven colling tower. That’s great! Or am I missing something?

[Henning]

I reckon they just fused a few atoms, like any basement physicist can do with a fusor, dpf or whatever. Maybe they even built a small tokamak. That picture is a torus? Yes? No?

[Henning]

Aeronaut wrote: The shipping container is made to order for international markets, if they emerge. Personally, the only international markets I see for any of the early manufacturers are countries that need lots of help with clean water and drainage even before electricity. Pro-bono work, which is designed into my plan.

???

Where’s that market that doesn’t want a FF generator?

BTW: The largest market of GE’s 2 MW gas turbines in shipping containers is Pakistan (even before the flooding), because there the grid is so bad, that companies and communities want backup systems to provide their energy needs without much outage.

[Henning]

You’ll need to pump out the atmospheric pressure anyway to replace it with fuel. Nitrogen and oxygen aren’t great fusion candidates.

Then the pinch wouldn’t occur with higher pressure. For D-D normally 7 torr (9 mbar) is used. FF reached 40 torr (53 mbar) accidentially. See https://focusfusion.org/index.php/site/article/simultaneous_firing_at_last_first_pinch_above_1_mega-amp_record-high_p/

The pressure of the fill gas is quite a parameter to tweak (one of the many variables), and there is no sound theory how to calculate it. An empirical simulation is available though, the so called Lee Model: http://www.plasmafocus.net/

[Henning]

Rezwan wrote: Can anyone draw up a schematic design of this? It’s easier to keep track with pictures.

Maybe we should start a section “Design” in the focusfusion.org-Wiki. Those things may be easier to talk about, when everyone can improve a design iteratively instead of working serially in a forum.

An example of open-source design is the RepRap project: http://www.reprap.org/wiki/Main_Page

And when it works, maybe also the Open Source Car project: http://www.theoscarproject.org/

By the way: The focusfusion.org-Wiki isn’t prominently linked, just from a single article, which I am too lazy to hunt down now. It should be in the headline, next to the forum-link.

[Henning]

JimmyT wrote: Let’s say you design your system to go after particles of 65Kev and were able to capture all the energy from them. Any particles of energy less than that would be decelerated, stopped and reversed by the induced magnetic field. Accelerating them back into the reaction chamber and taking some energy with them. Any particles faster than that will still have their residual velocity (the amount in excess of 65Kev ) when they reach the helium catchment container (Which thus may need cooling.)

There may be a way to mitigate this problem by using multiple coils. But I’m not sure how we would do that exactly.

What about using something similar to a mass spectrometer. Just that it doesn’t split the masses, but velocities. And behind that splitter set up an array of coils of different length.

[Author]

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