How long ago could we have built polywells? (WW II ?)

[krenshala]

My apologies.

From what little I know, my opinion is that the earliest a Polywell could have been made was probably somewhere around 1930. This is due to the fact that while superconductors help they aren't needed, but the vacuum tube tech at the time would have helped it a great deal (assuming those in the know are correct that the WBs worked extremely similarly to vacuum tubes).

[kunkmiester]

Electrons and ions in the polywell are in a vacuum, and affected by electric and magnetic fields. This knowledge is needed for building vacuum tubes that will work properly.

This knowledge was rendered to some extent obsolete when semiconductors were invented.

[KitemanSA]

Hmm. That is an interesting thought. Perhaps semi-conductors are one of the worst things that happened to us, diverting us from a future of energy independance.

Hmm.

[chrismb]

This knowledge is needed for building vacuum tubes that will work properly.

Really? Sounds like a remark that would be a worthy opening comment in a lecutre arguing for 'creationism'!

Did 'Caveman' understand combustion when making fire for the first time?

Remember my observation: NO plasma experiment has ever run as expected. Plasma kit always does something else. Sometimes more interesting. Sometimes a dud. But we know all we know about this, and now it is a case of getting on and building what we think we understand and seeing if it works.

The first 'proper working' of a vacuum tube was by Edison [or prob one of his minions] who recognised the rectifying flow from the hot filament of a lighting bulb. No knowledge present, but still 'correct valve operation'.

I think von Guericke deserves at least recognition here, if not credit, even if it isn't quite due! His seminal work on vacuums and electricity could hardly be matched for contribution to this field.

[D Tibbets]

As for vacuum tube understanding being obsolete. Bussard bemoaned this fact in his Google talk, when he complained that young physicists were idiots when it came to understanding vacuum tube technology and its application to certain aspects of the Polywell. As pointed out multi[ple times by M. Simon and others, some demonstrated vacuum tube products show behavior claimed for the Polywell. Some physists (A. Carlson) have ignored this in their criticisms, either through ignorance, despite, or laziness (unwilling to debate the relevance of the claims).

As for plasma experments being failures or resulting in unpredicted effects, this is a gross exaggeration, and is misleading. All of the work on Tokamaks, etc have greatly increased the understanding of plasma physics. And, of course, vacuum tube technology can perform reliably and repeatedly. The behavior of plasmas is complicated, and very susceptible to tiny variations in conditions, and limitations have not yet been fully resolved, but the understanding is much greater. A comparison of plasma behavior to fluid dynamics is appropriate. Many properties of plasmas are described with fluid dynamic approaches. The flow of gas in a jet engine, or a rocket, or scram jet engine can be very complicated and still is not fully described with a single set of equations. But, progress has been made, evidenced by all the planes flying around.

Dan Tibbets

[chrismb]

As pointed out multi[ple times by M. Simon and others, some demonstrated vacuum tube products show behavior claimed for the Polywell. Some physists (A. Carlson) have ignored this in their criticisms, either through ignorance, despite, or laziness (unwilling to debate the relevance of the claims).

In what way? Not sure I associate that with anything I've read.

As for plasma experments being failures or resulting in unpredicted effects, this is a gross exaggeration, and is misleading.

I'm not aware anyone mentioning any particular plasma experiments were failures. But, besides, please state a plasma experiment that resulted in zero unpredicted events.

[MSimon]

Sounds like a remark that would be a worthy opening comment in a lecutre arguing for 'creationism'!

You need vacuum tubes to prove creationism?

Who knew?

[kunkmiester]

The first 'proper working' of a vacuum tube was by Edison [or prob one of his minions] who recognised the rectifying flow from the hot filament of a lighting bulb. No knowledge present, but still 'correct valve operation'.

You kind of proved my point--Without that particular bit of knowledge(among others), you can't get it to work consistently. Who cares if he really knew the underlying issues? You're confusing total knowledge of the underlying physics with knowing enough to use it.

We use quantum physics models for so much, but all QP is probability. It's still useful though, right? Do we really need to find the underlying laws and conditions that lead to those(which, incidentally, would eliminate the probability) laws to make use of them?

Knowing that a polywell is essentially a vacuum tube vastly cuts down on the conditions that need to be studied. Over time people had built up a knowledge of how vacuum tubes worked(probably statistically to some extent) that accounted for various conditions and allowed for variables. They probably didn't have the knowledge in the form or amount I implied, which would be my error, but they had the knowledge, and used it. Do you need to know what rectification is called to use the principle to build a light bulb?

[MSimon]

If you do some searching around the 'net you can find old vacuum tube books online. I have read a lot of them. Some of the stuff is physics based some of it was empirical. And most of the books are of 1930s vintage.

[MSimon]

Uh, didn't some of the big AM transmitter 'valves' have metal rather than glass shells ? IIRC, they were water-cooled, could be disassembled for maintenance, then pumped down again. Similar tech was used for mercury-arc rectifiers, no ?

Yes, there were ceramic/metal based JAN WW II military tubes used in search radars for the 20 meter band. You can still fetch them on the Ebay if you wait. 15KW CB radio anyone?

EIMAC still makes high power ceramic/metal tubes. Used anywhere you need kilowatts and up RF.

[MSimon]

Let me add that the Debye length of the plasma was a consideration. Especially important near the cathode and plate. And this was in the 30s.

[ladajo]

As I recall the most powerful tube amplifier set in the world resides in Cutler, Maine. 2MW.
The transmitter deck was pretty cool, if you turned off the lights when the system was keyed up, and stood behind the main console, it was very star trekish. The amplifier enclosures glowing and all. The coupler room was pretty cool as well. Flourescent bulbs tied wrapped to the copper cage, lighting up when the array keyed up. Let you know in a simple way, "don't enter the couple cage".